An improved bound for strongly regular graphs with smallest eigenvalue $-m$

Fuente: arXiv
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Hauptverfasser: Koolen, Jack, Lv, Chenhui, Markowsky, Greg, Park, Jongyook
Format: Preprint
Veröffentlicht: 2025
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author Koolen, Jack
Lv, Chenhui
Markowsky, Greg
Park, Jongyook
author_facet Koolen, Jack
Lv, Chenhui
Markowsky, Greg
Park, Jongyook
contents In 1979, Neumaier gave a bound on $λ$ in terms of $m$ and $μ$, where $-m$ is the smallest eigenvalue of a primitive strongly regular graph, unless the graph in question belongs to one of the two infinite families of strongly regular graphs. We improve this result. We also indicate how our methods can be used to give an alternate derivation of Bruck's Completion Theorem for orthogonal arrays.
format Preprint
id arxiv_https___arxiv_org_abs_2506_04964
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An improved bound for strongly regular graphs with smallest eigenvalue $-m$
Koolen, Jack
Lv, Chenhui
Markowsky, Greg
Park, Jongyook
Combinatorics
05C50, 05E30
In 1979, Neumaier gave a bound on $λ$ in terms of $m$ and $μ$, where $-m$ is the smallest eigenvalue of a primitive strongly regular graph, unless the graph in question belongs to one of the two infinite families of strongly regular graphs. We improve this result. We also indicate how our methods can be used to give an alternate derivation of Bruck's Completion Theorem for orthogonal arrays.
title An improved bound for strongly regular graphs with smallest eigenvalue $-m$
topic Combinatorics
05C50, 05E30
url https://arxiv.org/abs/2506.04964