View source for Graph (mathematics)

: ''This article presents the essential definitions.  For a more complete account see ''[[graph theory]]''.  For another use of the term "graph" in mathematics, see ''[[graph of a function]]''.  For the more general concept of the graph of a relation, see ''[[relation (mathematics)|relation]]''.

[[Image:6n-graf.svg|thumb|250px|A labeled graph on 6 vertices and 7 edges.]]

In [[mathematics]] and [[computer science]], a '''graph''' is the basic object of study in [[graph theory]].  Informally speaking, a graph is a set of objects called ''points'' or ''vertices'' connected by links called ''lines'' or ''edges''.  In a graph proper, which is by default ''undirected'', a line from point ''A'' to point ''B'' is considered to be the same thing as a line from point ''B'' to point ''A''.  In a ''digraph'', short for ''directed graph'', the two directions are counted as being distinct ''arcs'' or ''directed edges''.  Typically, a graph is depicted in diagrammatic form as a set of dots (for the points, vertices, or nodes), joined by curves (for the lines or edges).