Inequivalent Regular Factors of Regular Graphs on 8 Vertices


Zoran_S. Radosavljević


In this paper we shall find all nonisomorphic factorizations of all regular graphs on 8 vertices into two regular factors without the use of a computer (as a contrast to [1]). These factorizations are significant since they produce regular graphs with the least eigenvalue $-2$ which are neither line-graphs nor cocktail-party graphs but which are cospectral to line-graphs (cf [1]).