ABSTRACT
The number of vertices of a graph (|V |) is called its order and the number of its edges (|E|) is called its size. In the context of this book, we will use the literals n for the order and m for the size of a graph. The complement of a graph G(V,E) is G(V,E ′) with the same vertex set as G and (u,v) ∈ E ′ if and only if (u,v) /∈ E . A clique in a graph is a set of vertices such that each vertex in this set is connected to all other vertices in the set. Figure 2.2 shows the complement of a graph and a clique of order 5 (K5).
