Refining with colors Mathematicians have developed various strategies to compare graphs. Since the 1970s, algorithms have been able to test graph isomorphism, but in exponential time.

Join Product: An operation on two graphs that connects every vertex of one graph with every vertex of the other, forming a new combined graph. Path: A sequence of distinct vertices in a graph ...

The study of such graphs is called graph theory. Engineers need to find planarity in a graph when, for example, they are designing a computer chip without a crossed wire.

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The main contribution of this work is a new type of graph product, which we call the zig-zag product. Taking a product of a large graph with a small graph, the resulting graph inherits (roughly) its ...

Paul M. Weichsel, The Kronecker Product of Graphs, Proceedings of the American Mathematical Society, Vol. 13, No. 1 (Feb., 1962), pp. 47-52 ...