An application of Hoffman graphs for spectral characterizations of graphs

Qianqian Yang; Aida Abiad Monge; Jack H. Koolen

doi:10.37236/6428

An application of Hoffman graphs for spectral characterizations of graphs

Qianqian Yang, Aida Abiad Monge, Jack H. Koolen^*

^*Corresponding author for this work

QE Operations research

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

In this paper, we present that the 2-clique extension of the (t + 1) x (t + 1)-grid is determined by its spectrum if t is large enough. By applying results of Gavrilyuk and Koolen, this implies that the Grassmann graph J(2)(2D, D) is determined by its intersection array as a distance-regular graph if D is large enough. The main tool we are using is Hoffman graphs.

Original language	English
Article number	P1.12
Number of pages	24
Journal	Electronic Journal of Combinatorics
Volume	24
Issue number	1
DOIs	https://doi.org/10.37236/6428
Publication status	Published - 20 Jan 2017

Keywords

Hoffman graph
graph eigenvalue
interlacing
walk-regular
spectral characterizations
SMALLEST EIGENVALUE

Access to Document

10.37236/6428Licence: CC BY

http://www.combinatorics.org/ojs/index.php/eljc/article/view/v24i1p12

Cite this

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KW - SMALLEST EIGENVALUE

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