We introduce a family of vertex-transitive graphs with specified subgroups of automorphisms which generalise Kneser graphs, powers of complete graphs and Cayley graphs of permutations. We compute the stability ratio for a wide class of these. Under certain conditions we characterise their stable sets of maximal size. © 2003 Elsevier Ltd. All rights reserved. MSC (2000): 05D05; 05C99

A graph is said to be half-arc-transitive if its automorphism group acts transitively on the set of its vertices and edges but not on the set of its arcs. With each half-arc-transitive graph of valency 4 a collection of the so called alternating cycles is associated, all of which have the same even length. Half of this length is called the radius of the graph in question. Moreover, any two adja...

This paper presents a solution of the polycirculant conjecture which states that every vertex-transitive graph G has an automorphism that permutes the vertices in cycles of the same length. This is done by identifying vertex-transitive graphs as coset graphs. For a coset graph H, an equivalence relation ∼ is defined on the vertices of cosets with classes as double cosets of the stabiliser and a...

The lackadaisical quantum walk is a lazy version of discrete-time, coined walk, where each vertex has weighted self-loop that permits the walker to stay put. They have been used speed up spatial search on variety graphs, including periodic lattices, strongly regular Johnson and hypercube. In these prior works, weights self-loops preserved symmetries graphs. this paper, we show can break all ver...

Finite graphs of valency 4 and girth 4 admitting 1 2-transitive group actions, that is vertex-and edge-but not arc-transitive group actions, are investigated. A graph is said to be 1 2-transitive if its automorphism group acts 1 2-transitively. There is a natural (balanced) orientation of the edge set of a 1 2-transitive graph induced and preserved by its auto-morphism group. Among others it is...

A generalization of some of the Folkman's constructions [13] of the so called semisymmetric graphs, that is regular graphs which are edgebut not vertex-transitive, was given in [22] together with a natural connection of graphs admitting 12 -arc-transitive group actions and certain graphs admitting semisymmetric group actions. This connection is studied in more detail in this paper. In Theorem 2...

We develop a new framework for analysing finite connected, oriented graphs of valency four, which admit a vertex-transitive and edge-transitive group of automorphisms preserving the edge orientation. We identify a sub-family of ‘basic’ graphs such that each graph of this type is a normal cover of at least one basic graph. The basic graphs either admit an edge-transitive group of automorphisms t...