New Feasibility Conditions for Directed Strongly Regular Graphs

  • Sylvia A. Hobart
  • Jason Williford
Keywords: Directed strongly regular graph

Abstract

We prove two results for directed strongly regular graphs that have an eigenvalue of multiplicity less than $k$, the common out-degree of each vertex. The first bounds the size of an independent set, and the second determines an eigenvalue of the subgraph on the out-neighborhood of a vertex. Both lead to new nonexistence results for parameter sets.
Published
2017-02-03
Article Number
P1.16