Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4655164 | Journal of Combinatorial Theory, Series A | 2016 | 28 Pages |
Abstract
We obtain several new results contributing to the theory of real equiangular line systems. Among other things, we present a new general lower bound on the maximum number of equiangular lines in d dimensional Euclidean space; we describe the two-graphs on 12 vertices; and we investigate Seidel matrices with exactly three distinct eigenvalues. As a result, we improve on two long-standing upper bounds regarding the maximum number of equiangular lines in dimensions d=14d=14 and d=16d=16. Additionally, we prove the nonexistence of certain regular graphs with four eigenvalues, and correct some tables from the literature.
Keywords
Related Topics
Physical Sciences and Engineering
Mathematics
Discrete Mathematics and Combinatorics
Authors
Gary Greaves, Jacobus H. Koolen, Akihiro Munemasa, Ferenc Szöllősi,