The graph tensor product, also called the graph cardinal product (Imrich 1998), graph categorical product, graph conjunction, graph direct product (Hammack et al. 2016), graph Kronecker product (Weichsel 1962), graph relational product, or graph weak direct product, is the graph product denoted and defined by the adjacency relations ( and ).
Letting denote the adjacency matrix, the graph tensor product of simple graphs and is given by
where denotes the Kronecker product (Hammack et al. 2016).
The graph tensor product is known as the bipartite double graph of .