pith. sign in

arxiv: 1405.3383 · v2 · pith:ITAKSJWZnew · submitted 2014-05-14 · 🧮 math.CO

Graphs with many valencies and few eigenvalues

classification 🧮 math.CO
keywords distinctgraphseigenvaluesthreevalenciesconnectedfourmany
0
0 comments X
read the original abstract

Dom de Caen posed the question whether connected graphs with three distinct eigenvalues have at most three distinct valencies. We do not answer this question, but instead construct connected graphs with four and five distinct eigenvalues and arbitrarily many distinct valencies. The graphs with four distinct eigenvalues come from regular two-graphs. As a side result, we characterize the disconnected graphs and the graphs with three distinct eigenvalues in the switching class of a regular two-graph.

This paper has not been read by Pith yet.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.