Cited by 143Advanced Differential Geometry ResearchAdvanced Algebra and GeometryHomotopy and Cohomology in Algebraic Topology

Some remarks about Lie groups transitive on spheres and tori

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Borel, Armand·1949·Bulletin of the American Mathematical Society

Abstract

The present note pertains principally to two papers of D. Montgomery and H. Samelson [l, 2J, 1 in which the authors study compact Lie groups transitive on tori [l] and spheres [2], I will here prove in another way, generalize, and sharpen a part of their results.§1 contains the remarks to [l], §2 to [2]; they are independent of one another and the methods used in both are quite different.I recall first the definition and some simple properties of homogeneous spaces.A manifold W is a homogeneous space under the Lie group 2 G if to each element a of G there corresponds a differentiate transformation T a 'x-^T a (x)of W into itself such that: (1) T a {x) depends continuously on the pair a£G, x£:W.(2) To the product (ab) corresponds the mapping x->T Ca b) (x)

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Crossref · 10.1090/s0002-9904-1949-09251-0

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  • Except for three cases, only the well-known groups can act transitively on a sphere: for even dimensions only the orthogonal group plus G2, for dimension 4n+1 the orthogonal, unimodular unitary, and unitary groups, and for dimension 4n-1 also the symplectic and full quaternion-unitary groups.

    “Except for three cases only those groups can act transitively on a sphere which are well known to do so, namely for even dimensions only the orthogonal group (plus G 2 , which has 5 6 as Klein space), for dimension 4w+l the orthogonal, the unimodular unitary, and the unitary group, for dimension 4n-1 also the symplectic group and the full quaternion-unitary group (plus 5 16 = B4/B3 and 5 7 = S 3 /”

    From Topology of Lie groups (1952) · cites this paper as [7]

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  • Any group that acts transitively and effectively on the torus T^n coincides with T^n.

    “A similar result is that any group acting transitively and effectively on the torus T n is actually T n itself [7; 90 ].”

    From Topology of Lie groups (1952) · cites this paper as [7]

    Section 1 states that a Lie group acting transitively and effectively on the n-dimensional torus is isomorphic to T^n, and Borel proves a related result for compact connected Lie groups. The citing sentence says “any group” without the Lie-group qualification, so it is broader than the result in our copy. No page number is available in the indexed passages. (LLM, conf=0.86)

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  • If a simply connected Klein space has characteristic 1, it is a single point; if characteristic 2, it is a sphere; if characteristic is a prime greater than 2, it is one of a small list of spaces.

    “If a (simply connected) Klein space has characeristic 1, it is a single point [127]; if it has characteristic 2, it is a sphere; if it has characteristic a prime>2, it is one of a small list of spaces [7; 127].”

    From Topology of Lie groups (1952) · cites this paper as [7]

    Theorems IV and V in §2 support the sphere and finite-list claims for simply connected spaces on which a compact connected Lie group acts transitively. Theorem IV specifies even-dimensional spheres. Our copy does not state that characteristic 1 implies a single point, and the citing sentence omits the restriction on the acting group. (LLM, conf=0.86)

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  • For spheres of even dimension, the isotropy group of a transitive transformation group must be a maximal subgroup of maximal rank.

    “For spheres of even dimension another approach has been given by A. Borel [7]: the sphere has characteristic two, and two is a prime number; this implies easily that the isotropy group must be a maximal subgroup of maximal rank, and now one can make use of the complete list of such groups in §25.”

    From Topology of Lie groups (1952) · cites this paper as [7]

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Research works printed but not linked: 2

  1. 4. E. Cartan, Sur les invariants intégraux de certains espaces homogènes clos . . . , Polskie Towarzystwo matematyczne, Krakow, Rocznik vol. 8 (1929) pp. 182-225
  2. 5. G. de Rham, Sur l’analysis situs des variétés à n dimensions. J. Math. Pures Appl. vol. 10 (1931) pp. 115-200.

Cited by

Sorted by citations

  • Topology of Lie groups

    Samelson, H. (1952) · Bulletin of the American Mathematical Society · doi:10.1090/s0002-9904-1952-09544-6 · Cited by 219

    “Borel [7]: the sphere has characteristic two, and two is a prime number; this implies easily that the isotropy group must be a maximal subgroup of maximal rank, and now one can make use of the complete list of such groups in §25.”
    Background

Authors
Borel, A.
Corresponding author
Borel, Armand
Venue
Bulletin of the American Mathematical Society
Published
1949
Volume
55
Issue
6
Pages
580-587
ISSN
  • 0002-9904 (ISSN-L)
  • 1088-9485
  • 0273-0979
OpenAlex
W2054095663
Cited by
143
References
9
Citations by year
2026: 1 · 2025: 3 · 2024: 2 · 2023: 3 · 2022: 3 · 2021: 5 · 2020: 4 · 2019: 2 · 2018: 2 · 2017: 11 · 2016: 3 · 2015: 4 · 2014: 8 · 2013: 2 · 2012: 7
FWCI
6.71
Type
journal article
Language
en
Open access
Locations
  • Bulletin of the American Mathematical Society (publishedVersion)
  • Project Euclid (Cornell University) (submittedVersion)
Topics
  • Physical Sciences › Mathematics › Geometry and Topology › Advanced Differential Geometry Research
  • Physical Sciences › Mathematics › Algebra and Number Theory › Advanced Algebra and Geometry
  • Physical Sciences › Mathematics › Mathematical Physics › Homotopy and Cohomology in Algebraic Topology
Keywords
compact Lie groups, transitive actions, homogeneous spaces, sphere, torus

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