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On Rank 3 Groups Having λ = 0

Published online by Cambridge University Press:  20 November 2018

M. D. Atkinson*
Affiliation:
University College, Cardiff, U.K.
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In this paper we shall consider certain rank 3 permutation groups G which act on a set Ω of size n. Thus a point stabiliser Gα will have 3 orbits { α }, △ (α), Γ (α) of sizes 1, k, I respectively. It is well known that, if |G| is even, then the orbital △ defines a strongly regular graph on Ω. In this graph, every point has valency k, every pair of adjacent points are adjacent to a constant number λ of common points, and every pair of non-adjacent points are adjacent to a constant number μ of common points. This notation is reasonably standard (see [4], where much background theory is given).

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1977

References

1. Atkinson, M. D., Rank 3 permutation groups with X = 0, Unpublished manuscript, Cardiff 1975.Google Scholar
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5. Sims, C. C., Primitive groups, graphs and block designs, Annals of New York Academy of Sciences 175, Article 1 (1970), 351353.Google Scholar