Spherical two-distance sets

dc.creatorMusin, Oleg R.
dc.date2008-01-24
dc.date2008-07-02
dc.date.accessioned2026-07-07T12:58:45Z
dc.date.available2026-07-07T12:58:45Z
dc.descriptionA set S of unit vectors in n-dimensional Euclidean space is called spherical two-distance set, if there are two numbers a and b, and inner products of distinct vectors of S are either a or b. The largest cardinality g(n) of spherical two-distance sets is not exceed n(n+3)/2. This upper bound is known to be tight for n=2,6,22. The set of mid-points of the edges of a regular simplex gives the lower bound L(n)=n(n+1)/2 for g(n. In this paper using the so-called polynomial method it is proved that for nonnegative a+b the largest cardinality of S is not greater than L(n). For the case a+b<0 we propose upper bounds on |S| which are based on Delsarte's method. Using this we show that g(n)=L(n) for 6<n<22, 23<n<40, and g(23)=276 or 277.
dc.description9 pages, (v2) several small changes and corrections suggested by referees, accepted in Journal of Combinatorial Theory, Series A
dc.identifierhttps://arxiv.org/abs/0801.3706
dc.identifierhttp://arxiv.org/abs/0801.3706
dc.identifierJournal of Combinatorial Theory, Series A 116 (2009) 988--995
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/225347
dc.subjectMetric Geometry
dc.subjectCombinatorics
dc.titleSpherical two-distance sets
dc.typetext

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