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On periodicity in series of related terms

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Walker, Gilbert Thomas·1931·Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character

Abstract

An important extension of our ideas regarding periodicity was made in 1927 when Yule pointed out that, instead of regarding a series of annual sunspot numbers as consisting merely of a harmonic series to which a series of random terms were added, we might suppose a certain amount of causal relationship between the successive annual numbers. In that case the system might be regarded as a physical system possessing one or more natural oscillations of its own, all subject to damping; and the effect of annual random disturbances would be to produce a fairly smooth curve with periods varying in amplitude and length, essentially as the sunspot numbers vary. If we call the departures from their mean of our series u1, u2.., Yule showed that the consequence of a single natural period is an equation like ux = kux-1 - ux-2 + vx, where vx represents the “accidental” external “disturbance”; and if there are two natural periods, ux = k1 (ux-1 + ux-3) - k2ux-2 - ux-4 + vx

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Metadata

Authors
Walker, G. T.
Venue
Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character
Published
1931-06-03
Volume
131
Issue
818
Pages
518-532
ISSN
  • 0950-1207 (ISSN-L)
  • 2053-9150
OpenAlex
W1983662669
Cited by
381
References
0
FWCI
1.97
Type
journal article
Language
en
Open access
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CoChat. (2026). Citation check: On periodicity in series of related terms. https://app.cochat.ai/papers/10.1098/rspa.1931.0069
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Walker, G. T. (1931). On periodicity in series of related terms. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character. https://doi.org/10.1098/rspa.1931.0069

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