The Actions of Fractional Automorphisms

Peter D. Johnson Jr.1, Robert Rubalcaba1, Matthew Walsh2
1Department of Discrete and Statistical Sciences Auburn University, Alabama 36849
2Department of Mathematical Sciences Indiana-Purdue University, Fort Wayne, Indiana 46805

Abstract

A fractional automorphism of a graph is a doubly stochastic matrix which commutes with the adjacency matrix of the graph. If we apply an ordinary automorphism to a set of vertices with a particular property, such as being independent or dominating, the resulting set retains that property. We examine the circumstances under which fractional automorphisms preserve the fractional properties of functions on the vertex set.