Просмотр кода страницы Graph, undirected graph, nonoriented graph

'''Graph, undirected graph, nonoriented graph''' --- граф, неориентированный граф. 

A '''graph''' consists of a finite set of '''vertices''' or '''nodes'''
<math>V</math>, a finite set of '''edges''' <math>E</math>, and a mapping <math>Ends</math> from <math>E</math> to
<math>V \times V</math> assigning to each edge <math>e</math> two, not necessarily
distinct, vertices of <math>V</math> (the extremities of <math>e</math>). The graph <math>G</math>
will be denoted by <math>G = (V, E, Ends)</math> or simply <math>G = (V, E)</math>. It is
easy to see that an edge <math>e = (v,w)</math> corresponds to an undirected
pair <math>(v,w)</math> of vertices. If we consider ordered pairs of
vertices <math>(v,w)</math>, we say about a ''directed graph'' with the
set of ''arcs'' <math>A = \{(v,w)\}</math>.