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SEMINARS
Dual Seidel switching and Deza graphs
时间  Datetime
2018-05-09 10:30 — 11:30 
地点  Venue
Large Conference Room
报告人  Speaker
Leonid Shalaginov
单位  Affiliation
Chelyabinsk State University
邀请人  Host
Yaokun Wu
报告摘要  Abstract

Permuting the rows (and not the columns) of the adjacency matrix of a graph is called dual Seidel switching. This operation was introduced in [H84] as a possible way to construct strongly regular graphs with λ=μ from the existing ones.

A k-regular graph G on v vertices is a Deza graph with parameters (v,k,b,a), where v>k≥b≥a≥0, if the number of common neighbours of two distinct vertices takes on one of two values a or b, not necessarily depending on the adjacency of the two vertices. A Deza graph is called a strictly Deza graph if it has diameter 2 and is not strongly regular. In [EFHHH99], the dual Seidel switching was adopted to obtain strictly Deza graphs from strongly regular graphs.

In this talk we give a survey of results on Deza graphs obtained by the dual Seidel switching. This is joint work in progress with Sergey Goryainov and Vladislav V. Kabanov.