Symmetries

Abstract

Automorphisms of graphs, hypergraphs and disgraphs are investigated. The invariance of the chromatic polynomial in the rotor effect is disproved. New invariance results are obtained. It is shown that given any integer k > 2 , almost every finite group acts as the regular full automorphism group of some k-uniform hypergraph. Permutation groups that can be represented as automorphism groups of digraphs are characterized.