👉 In graph theory, a coadjacency matrix (also known as adjacency matrix) is a square matrix used to represent the adjacency of a graph. It represents the degree of each vertex in the graph and its neighbors. The adjacency matrix is symmetric and non-negative semi-definite. The term "coadjacency" refers to the property that when two vertices are connected by an edge, their coadjacency matrix has a 1 at the diagonal corresponding to the edge's direction from one vertex to the
