Sesqui-Regular Graphs with Smallest Eigenvalue at Least $-3$

The Electronic Journal of Combinatorics 2026 Open access

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Authors: Qianqian Yang, Brhane Gebremichel, Masood Ur Rehman, Jae Young Yang, Jack H. Koolen
DOI: 10.37236/12174
Cited by: 1
References: 10

Abstract

Koolen Yang and Yang showed that if a graph with smallest eigenvalue at least $-3$ has large minimal valency, then it is $2$-integrable. In this paper, we show that sesqui-regular graphs with smallest eigenvalue at least $-3$ and parameters $(n,k,c)$, where $c \geq9$ and valency $k$ is sufficiently large, are $1$-integrable, and as a consequence we classify them.

Fields of Study & Subjects

Finite Group Theory Research Graph theory and applications Advanced Graph Theory Research

Publication details

Journal / source
The Electronic Journal of Combinatorics
Publisher
The Electronic Journal of Combinatorics
Volume
33
Issue
3
Publication date
7 August 2026
Language
EN