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Learning programs by learning from failures

Open access
Cropper, Andrew, Morel, Rolf·2021·Machine Learning

Abstract

We describe an inductive logic programming (ILP) approach called learning from failures. In this approach, an ILP system (the learner) decomposes the learning problem into three separate stages:generate,test, and constrain. In the generate stage, the learner generates a hypothesis (a logic program) that satisfies a set of hypothesis constraints(constraints on the syntactic form of hypotheses). In the test stage, the learner tests the hypothesis against training examples. A hypothesis fails when it does not entail all the positive examples or entails a negative example. If a hypothesis fails, then, in the constrain stage, the learner learns constraints from the failed hypothesis to prune the hypothesis space, i.e. to constrain subsequent hypothesis generation. For instance, if a hypothesis is too general (entails a negative example), the constraints prune generalisations of the hypothesis. If a hypothesis is too specific (does not entail all the positive examples), the constraints prune specialisations of the hypothesis. This loop repeats until either (i) the learner finds a hypothesis that entails all the positive and none of the negative examples, or (ii) there are no more hypotheses to test. We introduce Popper, an ILP system that implements this approach by combining answer set programming and Prolog. Popper supports infinite problem domains, reasoning about lists and numbers, learning textually minimal programs, and learning recursive programs. Our experimental results on three domains (toy game problems, robot strategies, and list transformations) show that (i) constraints drastically improve learning performance, and (ii) Popper can outperform existing ILP systems, both in terms of predictive accuracies and learning times.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper introduces learning from failures (LFF), an inductive logic programming approach that decomposes learning into generate, test, and constrain stages, using theta-subsumption to learn constraints from failed hypotheses and prune the hypothesis space. It implements LFF in Popper, combining ASP and Prolog, and reports that learned constraints drastically improve performance and that Popper can outperform Aleph, Metagol, ILASP2i, and ILASP3 on toy game, robot strategy, and list transformation tasks.

Key findings

  • On the buttons task, Popper learns programs with up to 10 body literals on both the small (p=20) and big (p=200) datasets, while Enumerate only reaches n=3 (small) and n=1 (big); Metagol reaches n=4 (50 s vs Popper’s 1 s) and n=3 (57 s vs Popper’s 8 s); ILASP2i and ILASP3 reach n=4 (small) and n=1 (big).
  • On robot strategies, Popper achieves the best predictive accuracy, is the fastest system, and is about 40 times quicker than Enumerate; Metagol almost always times out for grids larger than 20, ILASP3 cannot learn any solution in time even for a 10×10 world, and ILASP2i struggles as grid size grows.
  • On list transformations, Popper equals or outperforms Enumerate on all tasks (e.g., evens: 159 s for Enumerate vs 4 s for Popper) and equals or outperforms Metagol on all tasks except finddup, where Metagol has a 2% higher predictive accuracy; Aleph struggles except on addhead and threesame.
  • Popper scales well with respect to optimal solution size, number of background relations, domain size, number of training examples, and size of training examples; it is sensitive to the maximum number of unique variables and maximum number of clauses, but mostly insensitive to the maximum number of body literals.

Methods

  • The paper defines the LFF problem input (B, D, C, E+, E−), the size of the unconstrained hypothesis space, and generalisation/specialisation via theta-subsumption, proving soundness of generalisation and specialisation constraints and optimal-solution soundness of elimination constraints for separable definite programs.
  • Popper implements LFF: the generate stage uses ASP to declaratively encode, constrain, and search definite programs; the test stage uses Prolog to test hypotheses against examples and background knowledge with a timeout; the constrain stage learns ASP constraints (generalisation, specialisation, elimination, banish) from failed hypotheses, using Clingo’s multi-shot solving to maintain state.
  • Experiments cover three domains: buttons (p=20 and p=200, n=1..10, 200 positive and 200 negative examples, 1-minute timeout, 10 repetitions), robots (n×n grids for n=10..100, 20 positive and 20 negative training examples, 1000 positive and 1000 negative testing examples, 1-minute timeout, 10 repetitions), and list transformations (10 tasks, 10 positive and 10 negative training examples, 1000 positive and 1000 negative testing examples, max list length 50, 5-minute timeout, 10 repetitions), comparing Popper against Aleph, Metagol, ILASP2i, ILASP3, and Enumerate.

Limitations

  • Stated: Popper does not support non-observational predicate learning, predicate invention, negation/non-monotonic programs, or noisy examples; correctness results hold only when hypotheses are decidable/terminating (e.g., Datalog), and learned constraints are sound but not complete.
  • Stated: direct comparison of ILP systems is difficult because systems use different biases and excel at different problems; Popper is sensitive to the maximum number of unique variables and maximum number of clauses, though it can be robust to imperfect parameters in some tests.
  • Evident from the text: the evaluation is limited to three domains and does not test noise handling, predicate invention, non-observational predicate learning, or negation, so the reported advantages are not demonstrated for those settings.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1007/s10994-020-05934-z

Cites

77 of 77 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

35 of 102 cited sources checked · 22 supported · 0 flagged · accuracy not yet measured

  • Premisecitation
    § 1 Introduction · p. 2

    ASP-encoded ILP systems often struggle with scalability, especially in terms of the problem domain size.

    “Systems that implement this approach can often learn optimal and recursive programs and can harness state-of-the-art ASP solvers, but often struggle with scalability, especially in terms of the problem domain size.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Corapi et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Law et al. 2014 source
    • cites Schüller and Benz 2018 source

      The Related work section says ASP-based ILP introduced scalability limitations. It does not identify problem-domain size as a particular cause or dimension of those limitations; the Conclusion instead discusses scaling to large amounts of training examples. No page numbers are available in the supplied passages. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    Neo inherently requires SMT encoded properties for domain specific functions.

    “Neo inherently requires SMT encoded properties for domain specific functions (i.e. its background knowledge).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Feng et al. 2018 source
  • Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    Neo is not guaranteed to synthesise optimal (textually minimal) programs.

    “Neo cannot synthesise recursive programs, nor is it guaranteed to synthesise optimal (textually minimal) programs.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Feng et al. 2018 source
  • Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    Neo cannot synthesise recursive programs.

    “Neo cannot synthesise recursive programs, nor is it guaranteed to synthesise optimal (textually minimal) programs.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Feng et al. 2018 source
  • Premisereasoning
    § 2.3 Recursion · p. 7

    Many popular ILP systems, such as FOIL, Progol, TILDE, and Aleph struggle to learn recursive programs.

    “Indeed, many popular ILP systems, such as FOIL (Quinlan 1990), Progol (Muggleton 1995), TILDE (Blockeel and De Raedt 1998), and Aleph (Srinivasan 2001) struggle to learn recursive programs.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites Quinlan 1990 source

      The paper’s section on recursive definitions describes restrictions on the recursive clauses FOIL can learn, and §5.7 says its methods for avoiding infinite recursion are incomplete. But §5.7 also says FOIL can discover many common recursive definitions, so the broad claim that FOIL struggles to learn recursive programs overstates the limitation. The other systems have separate citations and are not assessed against this source. (LLM, conf=0.82)

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    • cites Muggleton 1995 source
    • cites Blockeel and De Raedt 1998 source
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    Premisereasoning
    § 2.1 Inductive program synthesis · p. 6

    Neo can fail to detect inconsistency with the examples, in which case no programs get pruned.

    “As it typically uses over-approximate properties, Neo can fail to detect inconsistency with the examples, in which case no programs get pruned.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Feng et al. 2018 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 1 Introduction · p. 2

    ASP-encoded ILP systems can often learn optimal and recursive programs.

    “Systems that implement this approach can often learn optimal and recursive programs and can harness state-of-the-art ASP solvers, but often struggle with scalability, especially in terms of the problem domain size.”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Corapi et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Law et al. 2014 source
    • cites Schüller and Benz 2018 source

      Section 4 describes searching for an optimal hypothesis, and Section 3.3 discusses configuring the hypothesis space to include a transitive-closure rule. These passages support optimal search and the possibility of recursive rules, but they do not establish that ASP-based ILP systems often learn recursive programs. The paper discusses scalability limitations in Section 7, without specifically identifying problem-domain size as the main limitation. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • May combine two claims.

    Interpretationcitation
    § 1 Introduction · p. 4

    Compared to Metagol, Popper does not need metarules, so can learn programs with any arity predicates.

    “Compared to Metagol, Popper does not need metarules (Cropper and Tourret 2020), so can learn programs with any arity predicates.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Cropper and Tourret 2020 source

      Section 2.1 says Metagol-style meta-interpretive learners use metarules, supporting the comparison’s Metagol side. The passages found do not discuss Popper, so they do not establish that Popper needs no metarules or can learn programs with predicates of any arity. Page numbers were not available in our copy. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Classified as probably not a substantial claim.

    Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    Neo synthesises non-recursive programs using SMT encoded properties and a three staged loop.

    “Neo (Feng et al. 2018) synthesises non-recursive programs using SMT encoded properties and a three staged loop.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Feng et al. 2018 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 1 Introduction · p. 2

    ILP systems naturally support lifelong and transfer learning because of their symbolic nature.

    “Finally, because of their symbolic nature, ILP systems naturally support lifelong and transfer learning (Cropper 2020), which is considered essential for human-like AI (Lake et al. 2016).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Cropper 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Lake et al. 2016 source
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    Premisecitation
    § 2.4 Optimality · p. 8

    Recent meta-level ILP approaches often learn optimal solutions, such as programs with the fewest clauses or literals.

    “Recent meta-level ILP approaches often learn optimal solutions, such as programs with the fewest clauses (Muggleton et al. 2015; Cropper and Muggleton 2016; Kaminski et al. 2018) or literals (Corapi et al. 2011; Law et al. 2014).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Muggleton et al. 2015 source
    • cites Cropper and Muggleton 2016 source
    • cites Kaminski et al. 2018 source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 2.5 Language bias · p. 8

    A user must either provide a set of metarules, or use a set of metarules restricted to a certain fragment of logic, e.g. dyadic Datalog.

    “Ausermusteither(i)provideasetofmetarules, or (ii) use a set of metarules restricted to a certain fragment of logic, e.g. dyadic Datalog (Cropper and Tourret 2020).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Cropper and Tourret 2020 source

      The Introduction says suitable metarules are commonly assumed to be supplied as background knowledge, and §3.1.1 studies syntactically restricted fragments. The paper also discusses chained dyadic Datalog, but these passages do not say a user must choose between supplying metarules and using a restricted fragment. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.5 Language bias · p. 8

    Mode declarations are a popular language bias.

    “Mode declarations (Muggleton 1995) are a popular language bias (Blockeel and De Raedt 1998; Srinivasan 2001; Ray 2009; Corapi et al. 2010, 2011; Athakravi et al. 2013; Ahlgren and Yuen 2013; Law et al. 2014).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Muggleton 1995 source
    • cites Blockeel and De Raedt 1998 source

      Section 4 (page unavailable) describes TILDE’s user-specified, PROGOL-like rmode specifications, which constrain allowable query refinements through variable modes and types. This supports the use of mode-based declarations as a language bias, but the paper does not establish that they are popular. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites Srinivasan 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.5 Language bias · p. 8

    Metarules are another popular syntactic bias used by many ILP approaches, including Metagol and, to an extent, ∂ ILP.

    “Metarules (Cropper and Tourret 2020) are another popular syntactic bias used by many ILP approaches (De Raedt and Bruynooghe 1992; Wang et al. 2014; Albarghouthi et al. 2017; Kaminski et al. 2018), including Metagol (Muggleton et al. 2015; Cropper et al. 2020; Cropper and Muggleton 2016) and, to an extent 5 , ∂ ILP (Evans and Grefenstette 2018).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Cropper and Tourret 2020 source
    • cites De Raedt and Bruynooghe 1992

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Wang et al. 2014 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.6 Answer set programming · p. 9

    Much recent work in ILP uses ASP to learn Datalog, definite, normal, and answer set programs.

    “Much recent work in ILP uses ASP to learn Datalog (Evans et al. 2019), definite (Muggleton et al. 2014; Kaminski et al. 2018; Cropper and Dumancic 2020), normal (Ray 2009; Corapi et al. 2011; Athakravi et al. 2013), and answer set programs (Law et al. 2014).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Evans et al. 2019 source
    • cites Muggleton et al. 2014 source
    • cites Kaminski et al. 2018 source
  • Classified as probably not a substantial claim.

    Premisecitation
    § 2.3 Recursion · p. 7

    Learning recursive programs has long been considered a difficult problem in ILP.

    “Learning recursive programs has long been considered a difficult problem in ILP (Muggleton et al. 2012).”
    • Also stated in: § 5.3 List transformation problem · p. 38 · plain
      “Learning recursive programs has long been considered a difficult problem in ILP (Muggleton et al. 2012)”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Muggleton et al. 2012 source
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    Premisecitation
    § 2.5 Language bias · p. 8

    The major problem with metarules is determining which one to use.

    “However, the major problem with metarules is determining whichonestouse(CropperandTourret2020).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Cropper and Tourret 2020 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.4 Optimality · p. 8

    Many ILP systems are not guaranteed to learn optimal solutions, where optimal typically means the smallest program or the program with the minimal description length.

    “Many ILP systems (Muggleton 1995; Srinivasan 2001; Blockeel and De Raedt 1998; Ray 2009) are not guaranteed to learn optimal solutions, where optimal typically means the smallest program or the program with the minimal description length.”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Muggleton 1995 source
    • cites Srinivasan 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Blockeel and De Raedt 1998 source

      Section 4 describes TILDE as selecting the best split at each node using a heuristic, while Section 5 compares the compactness of its theories with those of other ILP systems. This is consistent with the absence of a guarantee that TILDE finds the smallest theory, but the paper does not establish that many ILP systems lack such a guarantee or define optimality as the smallest program or minimum description length. Page numbers are unavailable in our copy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.7 Hypothesis constraints · p. 10

    INSPIRE also uses predefined constraints to remove redundancy from the hypothesis space.

    “INSPIRE (Schüller and Benz 2018) also uses predefined constraints to remove redundancy from the hypothesis space (in INSPIRE's case, each hypothesis is a single clause).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Schüller and Benz 2018 source

      Section 3.6 (Redundancy elimination module; page unavailable) describes constraints that eliminate redundant rules from INSPIRE’s hypothesis search space. But the parenthetical is not supported: Section 3 (Declarative hypothesis generation; page unavailable) says each generated answer set represents a single rule that may be part of a hypothesis, not that each hypothesis is a single clause. (LLM, conf=0.90)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 2.6 Answer set programming · p. 9

    ILASP can represent real numbers as strings and delegate the reasoning to Python via Clingo's scripting feature.

    “For instance, ILASP (Law et al. 2014) can represent real numbers as strings and delegate the reasoning to Python via Clingo's scripting feature (Gebser et al. 2014).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Law et al. 2014 source
    • cites Gebser et al. 2014 source
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    Premisecitation
    § 2.7 Hypothesis constraints · p. 10

    Many ILP systems allow a user to constrain the hypothesis space though clause constraints.

    “Many ILP systems allow a user to constrain the hypothesis space though clause constraints (Muggleton 1995; Srinivasan 2001; Blockeel and De Raedt 1998; Ahlgren and Yuen 2013; Law et al. 2014).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Muggleton 1995 source
    • cites Srinivasan 2001

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Blockeel and De Raedt 1998 source

      Section 4 says TILDE users specify which conjunctions may be added to queries, their maximum frequency, and variable modes and types. This supports user-imposed constraints on TILDE’s hypothesis search, but the passage does not establish that many ILP systems offer clause constraints specifically. No page number is available in our copy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
  • Classified as probably not a substantial claim.

    Premisecitation
    § 4.6 Popper loop and multi-shot solving · p. 28

    The idea of multi-shot solving is that state of the solving process for an ASP program can be saved to help solve modifications of that program.

    “The idea of multi-shot solving is that state of the solving process for an ASP program can be saved to help solve modifications of that program.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gebser et al. 2019 source
  • Classified as probably not a substantial claim.

    Premisecitation
    § 5.1.3 Results · p. 34

    Metagol performs iterative deepening over the number of clauses allowed in a solution.

    “Metagol performs iterative deepening over the number of clauses allowed in a solution (Muggleton et al. 2015).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Muggleton et al. 2015 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Algorithm 1 Popper · p. 20

    Other recent ILP approaches also employ defining an ASP problem where an answer set corresponds to a definite program.

    “The idea is to define an ASP problem where an answer set (a model) corresponds to a definite program, an approach also employed by other recent ILP approaches (Corapi et al. 2011; Law et al. 2014; Kaminski et al. 2018; Schüller and Benz 2018).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Corapi et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Law et al. 2014 source
    • cites Kaminski et al. 2018 source
  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § 4.6 Popper loop and multi-shot solving · p. 28

    In the multi-shot cycle, a ground program is given to an ASP solver, yielding an answer set, whose processing leads to a (first-order) extension of the program; only this extension then needs grounding and adding to the running ASP instance, which means that the running solver may maintain learned conflicts.

    “The essence of the multi-shot cycle is that a ground program is given to an ASP solver, yielding an answer set, who's processing leads to a (first-order) extension of the program. Only this extension then needs grounding and adding to the running ASP instance, which means that the running solver may, for example, maintain learned conflicts.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Gebser et al. 2019 source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
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    Premisecitation
    § 6.1.1 Features · p. 45

    Predicate invention helps reduce the size of target programs, which in turn reduces sample complexity and improves predictive accuracy.

    “Predicate invention has been shown to help reduce the size of target programs, which in turns reduces sample complexity and improves predictive accuracy (Cropper 2019; Dumancic et al. 2019).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites Cropper 2019 source
    • cites Dumancic et al. 2019 source

      Section 4.1 (page unavailable) reports improved predictive performance for models learned from the paper’s latent predicates. But Section 3.5’s reduction concerns candidate clauses pruned during search, not the size of target programs, and the copy does not establish reduced sample complexity or the claimed causal chain. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 5.2.1 Materials · p. 36

    It is impossible to generate a finite and complete set of metarules for a singleton-free fragment of monadic and dyadic Datalog.

    “It is impossible to generate a finite and complete set of metarules for a singleton-free fragment of monadic and dyadic Datalog (Cropper and Tourret 2020).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Cropper and Tourret 2020 source

      Section 5.3.1 (page unavailable) says the singleton-free fragment has no derivation reduction for arity at least two, supporting the claim if “complete” means derivationally complete. But the same summary says it has an entailment reduction to a finite set. The unqualified claim therefore overstates what is impossible. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
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    Findingown data
    § 6 Conclusions and limitations · p. 45

    Popper can substantially outperform existing ILP systems both in terms of predictive accuracies and learning times.

    “Popper can substantially outperform existing ILP systems both in terms of predictive accuracies and learning times”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § Abstract · p. 1

    Popper can outperform existing ILP systems, both in terms of predictive accuracies and learning times.

    “Our experimental results on three domains (toy game problems, robot strategies, and list transformations) show that (i) constraints drastically improve learning performance, and (ii) Popper can outperform existing ILP systems, both in terms of predictive accuracies and learning times.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 6 Conclusions and limitations · p. 45

    Popper scales well with respect to the optimal solution size, the number of background relations, the domain size, the number of training examples, and the size of the training examples.

    “Popper scales well with respect to the optimal solution size, the number of background relations, the domain size, the number of training examples, and the size of the training examples”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingnone given
    § 1 Introduction · p. 5

    Popper reasons about lists and infinite domains.

    “Popper support types, learning optimal (textually minimal) solutions, learning recursive programs, reasoning about lists and infinite domains, and hypothesis constraints.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Findingnone given
    § 1 Introduction · p. 5

    Popper uses hypothesis constraints.

    “Popper support types, learning optimal (textually minimal) solutions, learning recursive programs, reasoning about lists and infinite domains, and hypothesis constraints.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingown data
    § 2.5 Language bias · p. 8

    If suitable metarules are known, then Popper can simulate metarules through hypothesis constraints.

    “If suitable metarules are known, then, as we show in 'Appendix A', Popper can simulate metarules through hypothesis constraints.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data
    § 2.1 Inductive program synthesis · p. 7

    In our first two experiments, the hypothesis spaces contain approximately 10^6 and 10^16 rules.

    “By contrast, in our first two experiments (Sect. 5.1), the hypothesis spaces contain approximately 10 6 and 10 16 rules.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingreasoning
    § 1 Introduction · p. 4

    Popper does not pre-compute every rule, which allows it to learn rules with many body literals.

    “By contrast, Popper does not pre-compute every rule, which allows it to learn rules with many body literals.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingcitation
    § 1 Introduction · p. 4

    The key idea of Popper is that when a hypothesis fails, Popper uses theta-subsumption to translate the hypothesis itself into a set of hypothesis constraints to rule out generalisations and specialisations of it, which does not need a set of pre-computed rules and which is substantially quicker to compute.

    “By contrast, the key idea of Popper is that when a hypothesis fails, Popper uses theta-subsumption (Plotkin 1971) to translate the hypothesis itself into a set of hypothesis constraints to rule out generalisations and specialisations of it, which does not need a set of pre-computed rules and which is substantially quicker to compute.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Plotkin 1971

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given
    § 1 Introduction · p. 4

    Popper learns Prolog programs and cannot currently handle noise.

    “ILASP3 learns ASP programs and can handle noise, whereas Popper learns Prolog programs and cannot currently handle noise.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingreasoning
    § 2.1 Inductive program synthesis · p. 7

    Popper additionally learns definite programs, and thus supports learning programs with infinite domains.

    “Moreover, whereas ProSynth synthesises Datalog programs, Popper additionally learns definite programs, and thus supports learning programs with infinite domains.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Findingreasoning
    § 2.2 Inductive logic programming · p. 7

    In our approach continually builds a set of constraints.

    “In other words, in our approach continually builds a set of constraints.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 3.5.3 Constraints summary · p. 19

    Popper uses the learned constraints to learn definite programs.

    “In the next section we introduce Popper, which uses these constraints to learn definite programs.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § 5.1.1 Materials · p. 34

    When allowed up to ten body literals, Popper performs almost identically.

    “When allowed up to ten body literals, Popper performs almost identically.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingreasoning
    § 4.7 Worked example · p. 30

    Finally, Popper generates another hypothesis (h4), tests it against the examples, finds that it does not fail, and returns it.

    “Finally, Popper generates another hypothesis ( h4 ), tests it against the examples, finds that it does not fail, and returns it.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Findingnone given
    § 4 Popper · p. 19

    To learn optimal solutions, Popper searches for programs of increasing size.

    “To learn optimal solutions (Definition 14), Popper searches for programs of increasing size.”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim.

    Findingown data
    § 5.1.1 Materials · p. 34

    ILASP would not terminate in the time limit when given at most ten body literals because it pre-computes every rule in the hypothesis space.

    “when given this parameter ILASP would not terminate in the time limit because it pre-computes every rule in the hypothesis space.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § 4.7 Worked example · p. 30

    Popper generates another hypothesis (h3), tests it against the examples, and finds that it fails because it entails the negative example last([e,m,m,a],m) and is therefore too general.

    “Popper generates another hypothesis ( h3 ) and tests against the examples and finds that it fails because it entails the negative example last ( [ e , m , m , a ] , m ) and is therefore too general .”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingnone given
    § 4.3 Hypothesis constraints · p. 22

    Hypothesis constraints allow pruning recursive programs that do not contain a base case clause, left recursive or mutually recursive programs, or programs which contain subsumption redundancy between clauses.

    “For instance, hypothesis constraints allow us to prune recursive programs that do not contain a base case clause (Fig. 3), to prune left recursive or mutually recursive programs, or to prune programs which contain subsumption redundancy between clauses.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given
    § 4.2 Language bias constraints · p. 22

    Popper supports functional and irreflexive constraints, and constraints on recursive programs, such as disallowing left recursion or mutual recursion.

    “Popperalsosupports functional and irreflexive constraints, and constraints on recursive programs, such as disallowing left recursion or mutual recursion.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.7 Worked example · p. 30

    Popper adds the elimination constraint to the meta-level ASP program, which prunes h9 from the hypothesis space.

    “Popper adds this constraint to the meta-level ASP program which prunes h9 from the hypothesis space.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § 4.3 Hypothesis constraints · p. 22

    Popper supports hypothesis constraints, which are defined over a whole program rather than a single clause.

    “Popper additionally supports the more general concept of hypothesis constraints (Definition 6), which are defined over a whole program (a set of clauses) rather than a single clause (also employed in previous work (Athakravi et al. 2014)).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation
    § 4.2 Language bias constraints · p. 22

    Through constraints, Popper supports the standard notions of recall and input/output arguments of mode declarations.

    “Through constraints, Popper also supports the standard notions of recall and input/output 10 arguments of mode declarations (Muggleton1995).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Muggleton1995

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data
    § 5.1.3 Results · p. 34

    For the small dataset, the largest program that Metagol learns is for when n=4, which takes 50 seconds to learn, compared to one second for Popper.

    “For the small dataset, the largest program that Metagol learns is for when n = 4, which takes 50 seconds to learn, compared to one second for Popper.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation
    § 4.3 Hypothesis constraints · p. 22

    Popper supports clause constraints, which allow a user to prune specific clauses from the hypothesis space.

    “As with many ILP systems (Muggleton 1995; Srinivasan 2001; Athakravi et al. 2014; Law et al. 2014; Schüller and Benz 2018), Popper supports clause constraints, which allow a user to prune specific clauses from the hypothesis space.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Findingreasoning
    § 4.5.4 Specialisation constraints · p. 26

    The literal not clause(n) ensures that no additional clause is added to the n distinct clauses of the provided hypothesis.

    “The literal not clause( n ) ensures that no additional clause is added to the n distinct clauses of the provided hypothesis.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 5.1.3 Results · p. 35

    Popper outperforms ILASP2i and ILASP3 on both datasets.

    “PopperoutperformsILASP2iandILASP3onbothdatasets.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § 4.7 Worked example · p. 29

    Popper tests h1 against the examples and finds that it fails because it does not entail any positive example and is therefore too specific.

    “Popper then tests h1 against the examples and finds that it fails because it does not entail any positive example and is therefore too specific .”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.7 Worked example · p. 29

    Because h1 does not entail any positive example (is totally incomplete), Popper also generates an elimination constraint.

    “In addition, because h1 does not entail any positive example (is totally incomplete), Popper also generates an elimination constraint:”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.5.2 Encoding clauses · p. 24

    To ensure that variables are distinct, the inequalities V0!=V1, V0!=V2, and V1!=V2 must be imposed.

    “To ensure that variables are distinct we need to impose the inequality V0!=V1 and V0!=V2 and V1!=V2 .”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § 4.2 Language bias constraints · p. 22

    To add simple types to Popper requires the single constraint shown in Fig. 4.

    “For instance, to add simple types to Popper requires the single constraint shown in Fig. 4.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingreasoning
    § 4.5.4 Specialisation constraints · p. 26

    The first clause of h2 specialises both clauses in h1, yet h2 is not a specialisation of h1.

    “The first clause of h2 specialises both clauses in h1 , yet h2 is not a specialisation of h1 .”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given
    § 4.7 Worked example · p. 29

    Popper generates the simplest hypothesis h1.

    “To start, Popper generates the simplest hypothesis:”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.7 Worked example · p. 30

    Popper adds the generalisation constraint to the meta-level ASP program, which prunes h6 and h7 from the hypothesis space.

    “Popper adds this constraint to the meta-level ASP program which prunes h6 and h7 from the hypothesis space.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data
    § 5.1.3 Results · p. 34

    For the big dataset, the largest program that Metagol learns is for when n=3, which takes 57 seconds to learn, compared to eight seconds for Popper.

    “For the big dataset, the largest program that Metagol learns is for when n = 3, which takes 57 seconds to learn, compared to eight seconds for Popper.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given
    § 4 Popper · p. 19

    Popper implements the LFF approach and works in three separate stages: generate, test, and constrain.

    “Popper implements the LFF approach and works in three separate stages: generate, test, and constrain.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.7 Worked example · p. 29

    Popper adds the specialisation constraint to the meta-level ASP program, which prunes h2 and h5 from the hypothesis space.

    “Popper adds this constraint to the meta-level ASP program which prunes h2 and h5 from the hypothesis space.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § 4.5.2 Encoding clauses · p. 24

    The encoding allows for V0 = V1 = V2 = 0, where all the variables are A.

    “Note that the above encoding allows for V0 = V1 = V2 = 0 , where all the variables are A .”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data
    § 5.3.3 Results · p. 41

    Enumerate takes 159 seconds to find an evens program, whereas Popper takes only four seconds.

    “For instance, whereas it takes Enumerate 159 seconds to find an evens program, it takes Popper only four seconds.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 5.3.3 Results · p. 41

    Aleph struggles to learn solutions to these problems, with the exceptions of addhead and threesame, which do not need recursion.

    “Table 5 also shows that Aleph struggles to learn solutions to these problems. The exceptions are addhead and threesame , which do not need recursion.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingnone given
    § 5.2.3 Results · p. 37

    ILASP2i initially learns solutions in the given time limit, but struggles as the grid size grows.

    “ILASP2i initially learns solutions in the given time limit, but struggles as the grid size grows.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § 5.2.3 Results · p. 37

    When ILASP2i learns a solution, it is always an accurate solution.

    “Note that when ILASP2i learns a solution, it is always an accurate solution.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data
    § 5.4 Scalability · p. 42

    Popper scales well in the size of the optimal solution size and the number of background relations.

    “Our buttons experiment (Experiment 5.1) showed that Popper scales well in the size of the optimal solution size and the number of background relations.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § 6.1.1 Features · p. 45

    Popper can trivially learn Datalog programs and test them using ASP.

    “Popper can also trivially learn Datalog programs and test them using ASP.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingnone given
    § 5.3.1 Materials · p. 39

    When given the increment relation, Metagol runs into infinite recursion on almost every problem and could not find any solutions.

    “when given this relation Metagol runs into infinite recursion 18 on almost every problem and could not find any solutions.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § 5.4 Scalability · p. 42

    In Sect. 5.3, Popper and Metagol achieved similar performance.

    “To do so, we repeat the last experiment from Sect. 5.3, where Popper and Metagol achieved similar performance.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingnone given
    § 6 Conclusions and limitations · p. 45

    Popper combines ASP and Prolog to support types, learning optimal solutions, learning recursive programs, reasoning about lists and infinite domains, and hypothesis constraints.

    “Popper combines ASP and Prolog to support types, learning optimal solutions, learning recursive programs, reasoning about lists and infinite domains, and hypothesis constraints.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 5.2.3 Results · p. 37

    Popper outperforms ILASP2i and ILASP3 both in terms of predictive accuracies and learning times.

    “Popper outperforms ILASP2i and ILASP3 both in terms of predictive accuracies and learning times.”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim.

    Findingown data
    § 5.4.3 Results · p. 43

    Popper outperforms Metagol in all cases when varying the size of the input.

    “Popper outperforms Metagol in all cases.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Findingown data
    § 6 Conclusions and limitations · p. 45

    Popper is an ILP system that learns definite programs.

    “We implemented this approach in Popper, an ILP system that learns definite programs.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 5.4.3 Results · p. 42

    Given 10,000 examples, Metagol struggles to find a solution in one minute and eventually converges on the default predictive accuracy (50%).

    “Given this many examples, Metagol struggles to find a solution in one minute and eventually converges on the default predictive accuracy (50%).”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data
    § 5.3.3 Results · p. 41

    Although Aleph is sometimes faster than Popper, it only learns accurate solutions for addhead and threesame.

    “Note that although Aleph is sometimes faster than Popper, it only learns accurate solutions for addhead and threesame”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation
    § 6.1.1 Features · p. 45

    Popper does not support non-observational predicate learning, where examples of the target predicates are not directly given.

    “Unlike some ILP systems (Muggleton 1995; Katzouris et al. 2016), Popper does not support non-observational predicate learning (non-OPL) (Muggleton 1995), where examples of the target predicates are not directly given.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given
    § 5.2.3 Results · p. 37

    When Metagol learns a solution, it is always an accurate solution.

    “Note that when Metagol learns a solution, it is always an accurate solution.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingreasoning
    § 5.4.3 Results · p. 43

    The mean learning times of Popper for examples of length 50 and 500 are both less than a second.

    “The mean learning times of Popper for examples of length 50 and 500 are both less than a second.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data
    § 5.4.3 Results · p. 43

    The mean learning times for Metagol for examples of length 50 and 500 are 20 and 54 seconds respectively.

    “The mean learning times for Metagol for examples of length 50 and 500 are 20 and 54 seconds respectively.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given
    § 6.1.1 Features · p. 45

    Popper does not currently support predicate invention.

    “Popper does not currently support predicate invention.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given
    § 6.1.1 Features · p. 45

    Popper does not currently support noisy examples.

    “Popper does not currently support noisy examples.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § 1 Introduction · p. 4

    Compared to ILASP3, Popper does not need to ground a program, so scales better as the domain size grows.

    “Compared to ILASP3, Popper does not need to ground a program, so scales better as the domain size grows (Sect. 5.2).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Premisecitation
    § 1 Introduction · p. 2

    Set covering ILP systems tend to learn overly specific solutions and struggle to learn recursive programs.

    “However, these systems tend to learn overly specific solutions and struggle to learn recursive programs (Bratko 1999; Cropper et al. 2020).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Bratko 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Cropper et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisecitation
    § 1 Introduction · p. 2

    Because hypotheses are logic programs, they can be read by humans.

    “Because hypotheses are logic programs, they can be read by humans, crucial for explainable AI and ultra-strong machine learning (Michie 1988).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Michie 1988
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning
    § Abstract · p. 1

    The loop repeats until either the learner finds a hypothesis that entails all the positive and none of the negative examples, or there are no more hypotheses to test.

    “This loop repeats until either (i) the learner finds a hypothesis that entails all the positive and none of the negative examples, or (ii) there are no more hypotheses to test.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 1 Introduction · p. 2

    ILP systems can generalise from small numbers of examples, often a single example.

    “ILP systems can generalise from small numbers of examples, often a single example (Lin et al. 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Lin et al. 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Interpretationnone given
    § Abstract · p. 1

    In the generate stage, the learner generates a hypothesis (a logic program) that satisfies a set of hypothesis constraints.

    “In the generate stage, the learner generates a hypothesis (a logic program) that satisfies a set of hypothesis constraints (constraints on the syntactic form of hypotheses).”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 1 Introduction · p. 4

    ILASP3 is the most similar ILP approach and also employs a generate/test/constrain loop.

    “ILASP3(Law2018)isthemostsimilarILPapproachandalsoemploysagenerate/test/constrain loop.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Interpretationnone given
    § Abstract · p. 1

    In the test stage, the learner tests the hypothesis against training examples.

    “In the test stage, the learner tests the hypothesis against training examples.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationnone given
    § Abstract · p. 1

    The learning from failures (LFF) approach decomposes the ILP problem into three separate stages: generate, test, and constrain.

    “In this approach, an ILP system (the learner) decomposes the learning problem into three separate stages: generate , test , and constrain .”
    • Also stated in: § 1 Introduction · p. 2 · plain
      “In this approach, the learner (an ILP system) decomposes the ILP problem into three separate stages: generate , test , and constrain .”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The fundamental problem in ILP is to efficiently search a large hypothesis space.
  • Classified as probably not a substantial claim.

    Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    ProSynth takes as input a set of candidate Datalog rules and returns a subset of them.

    “ProSynth (Raghothaman et al. 2020) takes as input a set of candidate Datalog rules and returns a subset of them.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Raghothaman et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.1 Inductive program synthesis · p. 7

    ProSynth synthesises Datalog programs.

    “Moreover, whereas ProSynth synthesises Datalog programs, Popper additionally learns definite programs, and thus supports learning programs with infinite domains.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Raghothaman et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.5 Language bias · p. 8

    ILP approaches use a language bias to restrict the hypothesis space.

    “ILP approaches use a language bias (Nienhuys-Cheng and de Wolf 1997) to restrict the hypothesis space.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Nienhuys-Cheng and de Wolf 1997 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 2.5 Language bias · p. 8

    This limitation means that ILP systems that use metarules are difficult to use, especially when the BK contains predicate symbols with arity greater than two.

    “This limitation means that ILP systems that use metarules are difficult to use, especially when the BK contains predicate symbols with arity greater than two.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.1 Inductive program synthesis · p. 7

    The largest number of candidate rules considered in the ProSynth experiments is 1000.

    “For instance, the largest number of candidate rules considered in the ProSynth experiments is 1000.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Raghothaman et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.3 Recursion · p. 7

    Without recursion, it is often difficult for an ILP system to generalise from small numbers of examples.

    “Without recursion, it is often difficult for an ILP system to generalise from small numbers of examples (Cropper et al. 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cropper et al. 2015
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.1 Inductive program synthesis · p. 6

    ProSynth learns constraints that disallow certain clause combinations.

    “ProSynth learns constraints that disallow certain clause combinations, e.g. to prevent clauses that entail a negative example from occurring together.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Raghothaman et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation
    § 1 Introduction · p. 4

    ILASP3 uses a counter-example guided approach and translates an uncovered example e into a constraint that is satisfied if and only if e is covered.

    “Another way of viewing ILASP3 is that it uses a counter-example guided (Solar-Lezama et al. 2008) approach and translates an uncovered example e into a constraint that is satisfied if and only if e is covered.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Solar-Lezama et al. 2008

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § 2.5 Language bias · p. 8

    Compared with predicate (and mode) declarations, metarules are a much stronger inductive bias because they specify the exact form of clauses in the hypothesis space.

    “Compared with predicate (and mode) declarations, metarules are a much stronger inductive bias because they specify the exact form of clauses in the hypothesis space.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisecitation
    § 2.3 Recursion · p. 7

    These systems tend to learn overly specific solutions and struggle to learn recursive programs.

    “However, these systems tend to learn overly specific solutions and struggle to learn recursive programs (Bratko 1999; Cropper et al. 2020).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Bratko 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Cropper et al. 2020

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    Popper uses ASP to generate definite programs, which allows it to reason about large and infinite problem domains, such as reasoning about lists and real numbers.

    “Popper uses ASP to generate definite programs, which allows it to reason about large and infinite problem domains, such as reasoning about lists and real numbers.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Premisecitation
    § 3.2 Problem setting · p. 11

    The problem setting is based on the ILP learning from entailment setting.

    “Our problem setting is based on the ILP learning from entailment setting (De Raedt 2008).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites De Raedt 2008 source
  • May combine two claims.

    Interpretationown data
    § 3.3 Hypothesis space · p. 14

    The hypothesis space is huge for non-trivial inputs, which motivates using learned constraints to prune the hypothesis space.

    “As this result shows, the hypothesis space is huge for non-trivial inputs, which motivates using learned constraints to prune the hypothesis space.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.6 Answer set programming · p. 9

    If the hypothesis does not cover one of the examples, ILASP3 finds a reason why and then generates constraints to guide subsequent search.

    “If the hypothesis does not cover one of the examples, ILASP3 finds a reason why and then generates constraints to guide subsequent search.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.7 Hypothesis constraints · p. 10

    Athakravi et al. (2014) introduce domain-dependent constraints, which are constraints on the hypothesis space provided as input by a user.

    “Athakravi et al. (2014) introduce domain-dependent constraints , which are constraints on the hypothesis space provided as input by a user.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Athakravi et al. 2014 source
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    In this approach, the numeric computation is performed when grounding the inputs, so the grounding must be finite.

    “However, in this approach, the numeric computation is performed when grounding the inputs, so the grounding must be finite.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.6 Answer set programming · p. 9

    ILASP3's constraint loop requires at most | E | iterations, where | E | is the number of ILASP examples, which are partial interpretations.

    “ILASP3's constraint loop requires at most | E | iterations, where | E | is the number of ILASP examples, which are partial interpretations.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law et al. 2014 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 2.6 Answer set programming · p. 9

    With each iteration, ILASP3 finds the best hypothesis it can.

    “With each iteration, ILASP3 finds the best hypothesis it can.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § 3.2 Problem setting · p. 13

    There may be multiple (sometimes infinite) solutions to an LFF problem.

    “There may be multiple (sometimes infinite) solutions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 2.6 Answer set programming · p. 9

    ILASP3 learns unstratified ASP programs, including programs with choice rules and weak and hard constraints, and can handle noise.

    “ILASP3 learns unstratified ASP programs, including programs with choice rules and weak and hard constraints, and can handle noise.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationnone given
    § 2.7 Hypothesis constraints · p. 10

    Hypothesis constraints allow us to prune recursive programs without a base case and subsumption redundant programs.

    “Moreover, hypothesis constraints allow us to prune recursive programs without a base case and subsumption redundant programs.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    Popper does not pre-compute every clause, which allows it to learn clauses with many body literals.

    “By contrast, Popper does not pre-compute every clause, which allows it to learn clauses with many body literals.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 2.6 Answer set programming · p. 9

    Another way of viewing ILASP3 is that it uses a counter-example guided approach and translates an uncovered example e into a constraint that is satisfied if and only if e is covered.

    “Another way of viewing ILASP3 is that it uses a counter-example guided (Solar-Lezama et al. 2008) approach and translates an uncovered example e into a constraint that is satisfied if and only if e is covered.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Solar-Lezama et al. 2008

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given
    § 2.7 Hypothesis constraints · p. 10

    Through hypothesis constraints, Popper can enforce (optional) type, metarule, recall, and functionality restrictions.

    “For instance, through hypothesis constraints, Popper can enforce (optional) type, metarule, recall, and functionality restrictions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 3.4 Generalisations and specialisations · p. 14

    Midelfart (1999) extends subsumption to clausal theories.

    “Midelfart (1999) extends subsumption to clausal theories:”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Midelfart (1999) source
  • Classified as probably not a substantial claim.

    Premisecitation
    § 3.4 Generalisations and specialisations · p. 14

    Checking subsumption between clauses is decidable.

    “checking subsumption between clauses is decidable”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites NienhuysCheng and de Wolf 1997

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    A major limitation of most pure ASP-based ILP systems is the intrinsic grounding problem, especially on large domains, such as reasoning about lists or numbers-most ASP implementations do not support lists nor real numbers.

    “Therefore, a major limitation of most pure ASP-based ILP systems is the intrinsic grounding problem, especially on large domains, such as reasoning about lists or numbers-most ASP implementations do not support lists nor real numbers.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    Popper's constraints do not reason about specific clauses, but instead reason about the syntax of hypotheses using theta-subsumption and are therefore quick to compute.

    “Popper's constraints do not reason about specific clauses (because we do not pre-compute the hypothesis space), but instead reason about the syntax of hypotheses using theta-subsumption and are therefore quick to compute.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation
    § 3.4 Generalisations and specialisations · p. 14

    Checking entailment between clauses is undecidable.

    “whereas checking entailment between clauses is undecidable (Church 1936)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Church 1936 source
  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation
    § 2.6 Answer set programming · p. 9

    The constraints are boolean formulas over the rules in the hypothesis space, an approach that requires a set of precomputed rules.

    “The constraints are boolean formulas over the rules in the hypothesis space, an approach that requires a set of precomputed rules.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given
    § 2.7 Hypothesis constraints · p. 10

    Popper also allows a user to provide clause constraints.

    “Popper also allows a user to provide clause constraints.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation
    § 3.4 Generalisations and specialisations · p. 14

    If a clause C1 subsumes a clause C2, then C1 entails C2.

    “If a clause C 1 subsumes a clause C 2 then C 1 entails C 2 (Nienhuys-Cheng and de Wolf 1997).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Nienhuys-Cheng and de Wolf 1997 source
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationnone given
    § 2.6 Answer set programming · p. 9

    Popper learns Prolog programs, including programs operating over lists and real numbers, but cannot handle noise.

    “By contrast, Popper learns Prolog programs, including programs operating over lists and real numbers, but cannot handle noise.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning
    § 2.7 Hypothesis constraints · p. 10

    Popper also supports such constraints but goes further by learning constraints from failed hypotheses.

    “Popper also supports such constraints but goes further by learning constraints from failed hypotheses.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 3.4 Generalisations and specialisations · p. 14

    Subsumption is weaker than entailment.

    “Subsumption is therefore weaker than entailment.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: If C1 entails C2 then it does not necessarily follow that C1 subsumes C2.
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 3.4 Generalisations and specialisations · p. 14

    Deciding subsumption between clauses is NP-complete in general.

    “although, in general, deciding subsumption is a NP-complete problem (NienhuysCheng and de Wolf 1997)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites NienhuysCheng and de Wolf 1997

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 2.6 Answer set programming · p. 9

    Difficulty handling large (or infinite) domains is not specific to ASP.

    “Difficulty handling large (or infinite) domains is not specific to ASP.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: ∂ ILP uses a neural network to induce programs, but only works on BK formed of a finite set of ground atoms.
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given
    § 2.6 Answer set programming · p. 9

    When a hypothesis fails, Popper translates the hypothesis itself into a set of hypothesis constraints.

    “By contrast, when a hypothesis fails, Popper translates the hypothesis itself into a set of hypothesis constraints .”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation
    § 2.6 Answer set programming · p. 9

    ILASP3 is a pure ASP-based ILP system that also employs a constrain loop.

    “ILASP3 (Law 2018) is a pure ASP-based ILP system that also employs a constrain loop.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Law 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning
    § 4.1 Validity, redundancy, and efficiency constraints · p. 21

    Popper uses constraints to improve efficiency (mostly by removing redundancy), for instance by using variables in order.

    “Finally, Popper uses constraints to improve efficiency (mostly by removing redundancy). For instance, Popper uses constraints to use variables in order, which prunes the program p ( B ) :-q ( B ) because we could generate p ( A ) :-q ( A ) .”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Interpretationnone given
    § 4.6 Popper loop and multi-shot solving · p. 28

    A naive implementation of Algorithm 1, such as performing iterative deepening on the program size, would duplicate grounding and solving during the generate step.

    “A naive implementation of Algorithm 1, such as performing iterative deepening on the program size, would duplicate grounding and solving during the generate step.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § 4.1 Validity, redundancy, and efficiency constraints · p. 20

    Popper uses hypothesis constraints (in the form of ASP constraints) to eliminate answer sets, i.e. to prune the hypothesis space.

    “Popper uses hypothesis constraints (in the form of ASP constraints) to eliminate answer sets, i.e. to prune the hypothesis space.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning
    § 4.5.6 Banish constraints · p. 27

    The function banishConstraint ensures that no additional literals in clauses are allowed and no additional clauses are allowed when converting a hypothesis to an ASP encoded banish constraint.

    “The below function banishConstraint ensures both conditions when converting a hypothesis to an ASP encoded banish constraint.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § Algorithm 1 Popper · p. 20

    Popper uses ASP constraints to ensure that a definite program is declaration consistent and obeys hypothesis constraints, such as enforcing type restrictions or disallowing mutual recursion.

    “Popper uses ASP constraints to ensure that a definite program is declaration consistent and obeys hypothesis constraints, such as enforcing type restrictions or disallowing mutual recursion.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § 4.5.6 Banish constraints · p. 27

    When pruning a specific hypothesis, hypotheses with different variables should not be pruned.

    “To prune a specific hypothesis, hypotheses with different variables should not be pruned.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisecitation
    § 5.1.1 Materials · p. 34

    Metagol needs metarules to guide the proof search.

    “Metagol needs metarules (Sect. 2.5) to guide the proof search.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Sect. 2.5

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Study design and conductnone given
    § 5.1.1 Materials · p. 33

    To compare the systems, the authors try to use settings so that each system searches approximately the same hypothesis space.

    “To compare the systems, we try to use settings so that each system searches approximatelythesamehypothesisspace.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning
    § 5.1.1 Materials · p. 34

    The settings for Popper and Enumerate match those imposed by Metagol's metarules and somewhat ILASP's propositional representation.

    “These settings match those imposed by Metagol's metarules and somewhat ILASP's propositional representation.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § Algorithm 1 Popper · p. 20

    Adding learned hypothesis constraints eliminates answer sets and reduces the hypothesis space; the more constraints learned, the more the hypothesis space is reduced.

    “By later adding learned hypothesis constraints, we eliminate answer sets, and thus reduce the hypothesis space. In other words, the more constraints we learn, the more we reduce the hypothesis space.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § 4.1 Validity, redundancy, and efficiency constraints · p. 21

    Popper uses constraints to reduce redundancy, for instance by pruning subsumption redundant programs.

    “Popper also uses constraints to reduce redundancy. For instance, Popper prunes subsumption redundant programs, such as pruning the following program because the first clause subsumes the second:”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 4.5.4 Specialisation constraints · p. 26

    It is not possible for one of these clauses to be non-specialising, as each of the original n clauses is required to be specialised by a distinct clause.

    “It is not possible for one of these clauses to be non-specialising, as each of the original n clauses is required to be specialised by a distinct clause.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 5.1.1 Materials · p. 33

    Ensuring that the systems search identical hypothesis spaces is near impossible.

    “However,ensuringthatthesystemssearchidentical hypothesis spaces is near impossible.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Metagol performs automatic predicate invention and so considers a different hypothesis space to the other systems.
  • Classified as probably not a substantial claim.

    Study design and conductreasoning
    § 5.2 Robots · p. 35

    The authors purposely fix the optimal solution so that the only variable in the experiment is the domain size (i.e. the grid world size), which they progressively increase to evaluate how well the systems scale.

    “To reiterate, we purposely fix the optimal solution so that the only variable in the experiment is the domain size (i.e. the grid world size), which we progressively increase to evaluate how well the systems scale.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning
    § 5.1.3 Results · p. 35

    ILASP2i and ILASP3 both struggle on this problem because they pre-compute every clause in the hypothesis space, which means that they struggle to learn clauses with many body literals.

    “ILASP2i and ILASP3 both struggle on this problem because they pre-compute every clause in the hypothesis space, which means that they struggle to learn clauses with many body literals.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationcitation
    § 5.2.3 Results · p. 37

    The learning time of Popper does not increase as grid size grows because the domain size has no influence on the size of the learning from failures hypothesis space.

    “The reason that the learning time of Popper does not increase is that the domain size has no influence on the size of the learning from failures hypothesis space (Proposition 1).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Proposition 1

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning
    § 5.2.3 Results · p. 38

    The extra work done by ILASP3 is needed when learning general ASP programs, but in this special case (where there are no ILASP negative examples) it is unnecessary and computationally expensive.

    “The extra work done by ILASP3 is needed when learning general ASP programs, but in this special case (where there no ILASP negative examples) it is unnecessary and computationally expensive.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § 5.4.3 Results · p. 43

    Popper only uses the examples to test a hypothesis, so any increase in running time comes from executing the hypotheses using Prolog.

    “The reason is that Popper only uses the examples to test a hypothesis, so any increase in running time simply comes from executing the hypotheses using Prolog.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim.

    Interpretationnone given
    § 6 Conclusions and limitations · p. 44

    The learning-from-failures ILP approach decomposes the ILP problem into three separate stages: generate, test, and constrain.

    “Wehave described an ILP approach called learning from failures which decomposes the ILP problem into three separate stages: generate , test , and constrain .”
    Quote in the paperSubstantial claim
  • May combine two claims. The quote only partly states this claim.

    Interpretationreasoning
    § 5.2.3 Results · p. 37

    The decrease in Popper's learning time as grid size grows is explained by two factors: smaller programs that cover some positive examples but no negative examples become less likely to cover examples as grid size grows, and solutions have five or six literals with smaller solutions becoming more likely with increasing world size.

    “The reason for this is twofold. First, when the grid world is small, there are often many small programs that cover some of the positive examples but none of the negative examples”
    • Also stated in: § 5.2.3 Results · p. 37 · plain
      “Second, solutions have either five or six literals, with smaller solutions becoming more likely with increasing world size.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Interpretationnone given
    § 6.1.1 Features · p. 45

    Most of the paper's pruning techniques, except the elimination constraint, should extend to learning non-monotonic programs, such as Datalog with stratified negation.

    “For instance, most of our pruning techniques (except the elimination constraint) should extend to learning non-monotonic programs, such as Datalog with stratified negation.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § 5.2.3 Results · p. 38

    ILASP2i outperforms ILASP3 because once ILASP2i finds a solution it terminates, while ILASP3 finds one hypothesis schema that guarantees coverage of the example, then carries on to find alternative hypothesis schemas.

    “ILASP2i outperforms ILASP3 because once ILASP2i finds a solution it terminates. By contrast, ILASP3 finds one hypothesis schema that guarantees coverage of the example (which, in this special case, also implies finding a solution), then carries on to find alternative hypothesis schemas.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning
    § 5.5.1 Results · p. 44

    More variables implies more ways to form literals in a clause.

    “This result follows from Proposition 1 because more variables implies more ways to form literals in a clause.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § 5.2.2 Methods · p. 37

    Each experiment was repeated ten times and the standard error was plotted.

    “We repeat each experiment ten times and plot the standard error.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § 6.1.1 Features · p. 45

    Most of the results in this paper should extend to both the metarule-based and the prescriptive approaches to supporting predicate invention.

    “Most of the results in this paper should extend to both approaches.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data
    § 5.3.2 Methods · p. 39

    Each experiment was repeated 10 times and the standard error was plotted.

    “We repeat each experiment 10 times and plot the standard error.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning
    § 5.5.1 Results · p. 44

    Popper scales well with the maximum number of body literals, but can struggle with very large values for the maximum number of unique variables and clauses.

    “Overall these results suggest that Popper scales well with the maximum number of body literals, but can struggle with very large values for the maximum number of unique variables and clauses.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Interpretationreasoning
    § 5.2.3 Results · p. 37

    Metagol's performance degrades as grid size grows because Metagol searches for a hypothesis by inducing and executing partial programs over the examples, and as the grid size grows there are more partial programs to construct.

    “The reason is that Metagol searches for a hypothesis by inducing and executing partial programs over the examples. In other words, Metagol uses the examples to guide the hypothesis search. As the grid size grows, there are more partial programs to construct, so its performance suffers.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § 6.1.1 Features · p. 45

    Noise handling will likely increase learning times.

    “However, noise handling will likely increase learning times and future work should explore this trade-off.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 6.1.3 Better constraints · p. 46

    Refinement operators for clauses and theories have been studied in detail in ILP.

    “By contrast, refinement operators for clauses (Shapiro 1983; De Raedt and Bruynooghe 1993; Nienhuys-Cheng and de Wolf 1997) and theories (Nienhuys-Cheng and de Wolf 1997; Midelfart 1999; Badea 2001) have been studied in detail in ILP.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Shapiro 1983 source
    • cites De Raedt and Bruynooghe 1993
    • cites Nienhuys-Cheng and de Wolf 1997 source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning
    § 6.1.2 Better search · p. 46

    Decomposing the learning problem allows for a variety of algorithms and implementations, where each stage can be improved independently of the others.

    “Anadvantage of decomposing the learning problem is that it allows for a variety of algorithms and implementations, where each stage can be improved independently of the others.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § 6.1.1 Features · p. 45

    Most ILP systems handle noisy (misclassified) examples.

    “Most ILP systems handle noisy (misclassified) examples (Table 1).”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § 6.1.3 Better constraints · p. 46

    More complex types, such as polymorphic types, can achieve better pruning for programs over structured data.

    “However, more complex types, such as polymorphic types, can achieve better pruning for programs over structured data (Morel et al. 2019).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Morel et al. 2019 source
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § 6.1.2 Better search · p. 46

    Any improvement to the Popper ASP encoding that generates programs would have a major influence on learning times because it would reduce the number of programs to test.

    “For instance, any improvement to the Popper ASP encoding that generates programs would have a major influence on learning times because it would reduce the number of programs to test.”
    Quote in the paperNot a substantial claim
162 of 162
  • The paper relies on this without support.

    The fundamental problem in ILP is to efficiently search a large hypothesis space.

    “The fundamental problem in ILP is to efficiently search a large hypothesis space (the set of all hypotheses).”
  • The paper relies on this without support.

    ILASP3 learns ASP programs and can handle noise.

    “ILASP3 learns ASP programs and can handle noise, whereas Popper learns Prolog programs and cannot currently handle noise.”
  • The paper relies on this without support.

    ILASP3 pre-computes every rule in the hypothesis space and therefore struggles to learn rules with many body literals.

    “ILASP3 pre-computes every rule in the hypothesis space and therefore struggles to learn rules with many body literals (Sect. 5.1).”
  • The paper relies on this without support.

    With each iteration, ILASP3 finds the best hypothesis it can.

    “With each iteration, ILASP3 finds the best hypothesis it can.”
  • The paper relies on this without support.

    If the hypothesis does not cover one of the examples, ILASP3 finds a reason why and then generates constraints to guide subsequent search.

    “If the hypothesis does not cover one of the examples, ILASP3 finds a reason why and then generates constraints to guide subsequent search.”
  • The paper relies on this without support.

    The constraints are boolean formulas over the rules in the hypothesis space, an approach that requires a set of pre-computed rules and the computation of which can be very expensive.

    “The constraints are boolean formulas over the rules in the hypothesis space, an approach that requires a set of pre-computed rules and the computation of which can be very expensive.”
  • The paper relies on this without support.

    Aleph can learn recursive programs but struggles because it requires examples of both the base and inductive cases.

    “Aleph can learn recursive programs but struggles because it requires examples of both the base and inductive cases.”
  • The paper relies on this without support.

    It is often infeasible to pre-compute the full hypothesis space.

    “This difference is important because it is often infeasible to pre-compute the full hypothesis space.”
  • The paper relies on this without support.

    There are often multiple (sometimes infinite) hypotheses that explain the data.

    “There are often multiple (sometimes infinite) hypotheses that explain the data.”
  • The paper relies on this without support.

    ∂ ILP uses a neural network to induce programs, but only works on BK formed of a finite set of ground atoms.

    “For instance, ∂ ILP uses a neural network to induce programs, but only works on BK formed of a finite set of ground atoms.”
  • The paper relies on this without support.

    If C1 entails C2 then it does not necessarily follow that C1 subsumes C2.

    “However, if C 1 entails C 2 then it does not necessarily follow that C 1 subsumes C 2.”
  • The authors state this as an assumption.

    A hypothesis H is a definite program.

    “This proof relies on a hypothesis H being (i) a definite program and (ii) separable.”
  • The authors state this as an assumption.

    A hypothesis H is separable.

    “This proof relies on a hypothesis H being (i) a definite program and (ii) separable.”
  • The paper relies on this without support.

    No other ILP system supports hypothesis constraints with the same ease and flexibility as Popper.

    “We are unaware of any other ILP system that supports hypothesis constraints, at least with the same ease and flexibility as Popper.”
  • The authors state this as an assumption.

    In practice, every solution terminates before the timeout enforced when testing programs.

    “In practice, such as in our experiments on learning list transformation programs, we enforce a timeout when testing programs, i.e. we assume that every solution terminates before the timeout.”
  • The paper relies on this without support.

    Metagol performs automatic predicate invention and so considers a different hypothesis space to the other systems.

    “For instance, Metagol performs automatic predicate invention and so considers a different hypothesis space to the other systems.”
  • The paper relies on this without support.

    If a clause or literal fails during the search, Metagol does not remember this failure, and will retry already failed clauses and literals at each depth (and even multiple times as the same depth).

    “However, if a clause or literal fails during the search, Metagol does not remember this failure, and will retry already failed clauses and literals at each depth (and even multiple times as the same depth).”
  • The paper relies on this without support.

    ILASP2i and ILASP3 do not support lists.

    “Because ILASP2i and ILASP3 do not support lists, we only compare Popper, Enumerate, Metagol, and Aleph.”
  • The paper relies on this without support.

    No existing ILP system can learn optimal solutions for all of these tasks without being provided with a strong inductive bias.

    “As far as we are aware, no existing ILP system can learn optimal solutions for all of these tasks without being provided with a strong inductive bias.”
  • The paper relies on this without support.

    Metagol does not easily support triadic relations.

    “We exclude this relation from the other experiments because Metagol does not easily support triadic relations.”
  • The paper relies on this without support.

    Popper and Enumerate can generate non-terminating Prolog programs.

    “Because Popper and Enumerate can generate non-terminating Prolog programs, we set both systems to use a testing timeout of 0.1 seconds per example.”
  • The paper relies on this without support.

    To learn solutions that generalise, an ILP system needs to support recursion and large domains.

    “To learn solutions that generalise, an ILP system needs to support recursion and large domains.”
  • The paper relies on this without support.

    The list transformation tasks used in the experiments are representative of complex and recursive list transformation programs.

    “Overall, the results from this experiment suggest that (i) the answer to question Q1 is again yes, constraints improve learning performance, and (ii) Popper can outperform other ILP systems when learning complex and recursive list transformation programs.”
  • The authors state this as an assumption.

    A predictive accuracy of 50% indicates that a system has failed to learn a program in the given amount of time.

    “When a system has 50% accuracy, it means that the system has failed to learn a program in the given amount of time, and so achieves the default accuracy.”
24 of 24

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Popper relies on manually defined mode declarations to control the search.

    “While more flexible than template-based methods, Popper still relies on manually defined mode declarations to control the search.”

    From ADVENT: LLM-Driven Automatic Predicate Invention for ILP (2026) · cites this paper as [3]

    Section 2.5 (p. 8) explicitly says, “We do not use mode declarations,” and identifies predicate declarations as Popper’s simpler language bias. Section 4.2 (p. 22) says Popper can optionally express some features of mode declarations through hypothesis constraints, but that does not mean it relies on manually defined mode declarations. (LLM, conf=0.95)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured
  • LFE is by far the most popular ILP setting.

    “LFE is by far the most popular ILP setting (Shapiro, 1983; Muggleton, 1987; Muggleton & Buntine, 1988; Muggleton & Feng, 1990; Quinlan, 1990; Muggleton, 1995; Bratko, 1999; Srinivasan, 2001; Ray, 2009; Ahlgren & Yuen, 2013; Muggleton et al., 2015; Cropper & Muggleton, 2016; Kaminski et al., 2018; Cropper & Morel, 2021).”

    From Inductive Logic Programming At 30: A New Introduction (2022) · cites this paper as Cropper & Morel, 2021

    Section 3.2 (p. 11) says the paper’s problem setting is based on ILP learning from entailment, so the source is an example of that setting. It does not say that learning from entailment is the most popular ILP setting, let alone by far. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • Context-dependent examples improve the grounding problem compared to not using them, but the approach still needs a finite grounding for each example and still struggles as the domain size increases.

    “Although this approach is shown to improve the grounding problem compared to not using context-dependent examples, the approach still needs a finite grounding for each example and still struggles as the domain size increases (Cropper & Morel, 2021).”

    From Inductive Logic Programming At 30: A New Introduction (2022) · cites this paper as Cropper & Morel, 2021

    Section 5.1.1 (p. 33) says the authors used context-dependent examples with ILASP, while Section 2.6 (p. 9) describes finite grounding and difficulty with large domains as limitations of ASP-based approaches. The paper does not show that context-dependent examples improve grounding compared with not using them, or specifically establish a finite-grounding requirement for each such example. (LLM, conf=0.83)

    Experimental — accuracy not yet measured
  • Classical inductive logic programming (ILP) can learn inference rules from examples rather than requiring manual specification.

    “Classical inductive logic programming (ILP) Muggleton [1991], Cropper and Morel [2021] can learn such rules from examples rather than requiring manual specification”

    From Reason Popper-ly: Patching In-Context Reasoning with Inductive Logic Programming (2026) · cites this paper as Cropper and Morel [2021]

  • Some systems induce theories formed of multiple clauses and thus require generality orders over clausal theories.

    “However, some systems (Shapiro, 1983; Bratko, 1999; Cropper & Morel, 2021) induce theories formed of multiple clauses and thus require generality orders over clausal theories .”

    From Inductive Logic Programming At 30: A New Introduction (2022) · cites this paper as Cropper & Morel, 2021

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Separable programs are said to include recursive programs

    Minor

    The definition excludes a program whose predicate appears in both a clause head and a clause body. That excludes recursion within the program, contrary to the statement that separable programs include recursive programs.

  • Answer-set example omits a predicate arity

    Minor

    The connected example uses a three-argument body_literal, whereas the stated encoding gives body_literal four arguments, including the predicate's arity.

  • Cons declaration has the wrong arity

    Minor

    The appendix declares cons with arity 2, but its three argument types and directions describe an arity-3 predicate. The materials also explicitly call it cons/3.

  • Increment is assigned to different list experiments

    Minor

    The materials say increment is included in the len experiment, while Appendix D says it is only given in the sorted experiment.

4 of 4

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Law, M. (2018). Inductive learning of answer set programs. Ph.D. thesis, Imperial College London, UK.
  2. Srinivasan, A. (2001). The ALEPH manual. Machine Learning at the Computing Laboratory: Oxford University.

Cited by

Sorted by citations

Authors
Cropper, A., & Morel, R.
Affiliations
University of Oxford (GB)
Corresponding author
Cropper, Andrew
Venue
Machine Learning
Published
2021-02-19
Volume
110
Issue
4
Pages
801-856
ISSN
  • 0885-6125 (ISSN-L)
  • 1573-0565
OpenAlex
W3022490130
Cited by
86
References
71
Citations by year
2026: 10 · 2025: 23 · 2024: 11 · 2023: 21 · 2022: 9 · 2021: 10 · 2020: 1
FWCI
4.43
Type
journal article
Language
en
Open access
Locations
  • Machine Learning (publishedVersion, cc-by)
  • arXiv (Cornell University) (submittedVersion)
  • arXiv (Cornell University)
Funders
University of Oxford
Topics
  • Physical Sciences › Computer Science › Artificial Intelligence › Logic, Reasoning, and Knowledge
  • Physical Sciences › Computer Science › Information Systems › Data Mining Algorithms and Applications
  • Physical Sciences › Computer Science › Artificial Intelligence › AI-based Problem Solving and Planning
Keywords
learning from failure, inductive logic programming, Karl Popper, answer set programming, Prolog

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-19.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-19.

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