1. Graph theory
This section presents the basic definitions, terminology and notation of graph theory, along with some fundamental results. Further information can be found in the many standard books on the subject – for example, Bondy and Murty , Chartrand, Lesniak and Zhang , Gross and Yellen  or West , or, for a simpler treatment, Marcus  or Wilson .
A graph G is a pair of sets (V, E), where V is a finite non-empty set of elements called vertices, and E is a finite set of elements called edges, each of which has two associated vertices. The sets V and E are the vertex-set and edge-set of G, and are ...