The Lemmens-Seidel conjecture and forbidden subgraphs

In this paper we show that the conjecture of Lemmens and Seidel of 1973 for systems of equiangular lines with common angle \(\arccos (1/5)\) is true. Our main tool is forbidden subgraphs for smallest Seidel eigenvalue \(-5\).

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Bibliographic Details
Published in:arXiv.org 2020-03
Main Authors: Meng-Yue, Cao, Jack, H, Koolen, Yen-Chi, Roger Lin, Wei-Hsuan, Yu
Format: Article
Language:English
Subjects:
Eigenvalues
Graph theory
Online Access:Get full text
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Summary:In this paper we show that the conjecture of Lemmens and Seidel of 1973 for systems of equiangular lines with common angle \(\arccos (1/5)\) is true. Our main tool is forbidden subgraphs for smallest Seidel eigenvalue \(-5\).
ISSN:2331-8422