On Matrix Product Factorization of graphs

Abstract

In this paper, we explore the concept of the ``matrix product of graphs," initially introduced by Prasad, Sudhakara, Sujatha, and M. Vinay. This operation involves the multiplication of adjacency matrices of two graphs with assigned labels, resulting in a weighted digraph. Our primary focus is on identifying graphs that can be expressed as the graphical matrix product of two other graphs. Notably, we establish that the only complete graph fitting this framework is $K_{4n+1}$, and moreover the factorization is not unique. In addition, the only complete bipartite graph that can be expressed as the graphical matrix product of two other graphs is $K_{2n,2m}$ Furthermore, we introduce several families of graphs that exhibit such factorization and, conversely, some families that do not admit any factorization such as wheel graphs, friendship graphs, hypercubes and paths.