INTRODUCTION TO GRAPH THEORY
n mathematics , graph theory is the study of graphs , which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of vertices (also called nodes or points ) which are connected by edges (also called links or lines ). A distinction is made between undirected graphs , where edges link two vertices symmetrically, and directed graphs , where edges link two vertices asymmetrically. Graphs are one of the principal objects of study in discrete mathematics . Definitions [ edit ] Further information: Glossary of graph theory Definitions in graph theory vary. The following are some of the more basic ways of defining graphs and related mathematical structures . Graph [ edit ] A graph with three vertices and three edges. In one restricted but very common sense of the term, [1] [2] a...