A 1978 theorem of Kozen states that two graphs on n vertices are isomorphic if and only if there is a clique of size n in the weak modular product between the two graphs. Restricting to bipartite graphs and considering complete bipartite subgraphs (bicliques) therein, we study the combinatorics of the weak modular product. We identify cases where isomorphism is tractable using this approach, wh...

Calculating a product of multiple graphs has been studied in mathematics, engineering, computer science, and more recently in network science, particularly in the context of multilayer networks. One of the important questions to be addressed in this area is how to characterize spectral properties of a product graph using those of its factor graphs. While several such characterizations have alre...

W apply random graph modeling methodology to analyze bipartite consumer-product graphs that represent sales transactions to better understand consumer purchase behavior in e-commerce settings. Based on two real-world e-commerce data sets, we found that such graphs demonstrate topological features that deviate significantly from theoretical predictions based on standard random graph models. In p...

The design of LDPC codes based on a class of expander graphs is investigated. Graph products, such as the zig-zag product [9], of smaller expander graphs have been shown to yield larger expanders. LDPC codes are designed based on the zigzag product graph of two component Cayley graphs. The results for specific cases simulated reveal that the resulting LDPC codes compare well with other random L...

A graph G is balanced if the maximum ratio of edges to vertices, taken over all subgraphs of G, occurs at G itself. This note uses the maxow/min-cut theorem to prove a good characterization of balanced graphs. This characterization is then applied to some results on how balanced graphs may be combined to form a larger balanced graph. In particular, we show that edge-transitive graphs and comple...