1.3 Undirected Graph

If the edges of GG are unordered pairs, GG is a undirected graph. In an undirected graph, v,w=w,v(v,w)=(w,v). If edge ee of an undirected graph is represented by v,w(v,w), then vv is adjacent to ww and ww is adjacent to vv. The terminology “undirected graph” is somewhat cumbersome. In this document, undirected graphs are often referred to as just “graphs”.

Figure 2 depicts an undirected graph with six vertices and eight edges. The fact that the graph is undirected is indicated by the absence of directionality arrows.

Figure 2: Example of an Undirected Graph