The document discusses relation matrices, which are zero-one matrices that can represent relations between finite sets. A relation matrix has rows and columns corresponding to the elements of the domain and range sets, with 1s indicating which pairs are in the relation and 0s indicating which pairs are not. The document provides examples of defining relations from sets and constructing their relation matrices. It also outlines properties that relation matrices must have if the relation is reflexive, symmetric, or antisymmetric.