raphs Definition. a directed graph(digraph G=(, E) is an ordered pair consisting of a set v of vertices(singular: vertex ● a set e∈ x y ofedges. In an undirected graphG=(v, E), the edge set e consists of unordered pairs of vertices In either case, we have E=O(2). Moreover, if G is connected, then E≥-1G h rap s D fi i i Definition. A di d h rected graph (di h grap ) G = (V, E) is an ordered pair consisting of y a set V of vertices (i l s ngu ar: vertex), y a set E ∈ V × V of edges. In an undirected graph G = (V, E), the edge set E consists of unordered pairs of vertices. In either case, we have |E| = O(V2). Moreover, if G is connected then is connected, then |E| ≥ |V| – 1