Graph
Graph [ edit ] A graph with three vertices and three edges. In one restricted but very common sense of the term, [1] [2] a graph is an ordered pair � = ( � , � ) comprising: � , a set of vertices (also called nodes or points ); � ⊆ { { � , � } ∣ � , � ∈ � and � ≠ � } , a set of edges (also called links or lines ), which are unordered pairs of vertices (that is, an edge is associated with two distinct vertices). To avoid ambiguity, this type of object may be called precisely an undirected simple graph . In the edge { � , � } , the vertices � and � are called the endpoints of the edge. The edge is said to join � and � and to be incident on � and on � . A vertex may exist in a graph and not belong to an edge. Multiple edges , not allowed u...