06.02.2012 Lecturer: Hiroki Koike

Title: Isomorphic Tetravalent cyclic Haar graphs

Abstract: Let S be a subset of the cyclic group Zn. The cyclic Haar graph H(Zn,S) is the bipartite graph with vertex set two copies of the cyclic group and edges {x,y} where x and y are in Zn and x-y is in S. We give necessary and sufficient conditions for the isomorphism of two connected cyclic Haar graphs of valency 4.