ABSTRACT

Chapter 4 laid out the definitions of four standard graph products: the Cartesian product, the direct product, the strong product, and the lexicographic product. It also demonstrated that it is these four products alone-among all possible associative graph products of the type considered here-that involve the structure of both factors in a meaningful way, and have the additional property that at least one projection is a weak homomorphism. For this reason the four standard products are, by far, the most extensively studied, and have the widest range of applications. They are thus the primary topics of this book.