# graph

graph, figure that shows relationships between quantities. The graph of a function *y* = *f* ( *x* ) is the set of points with coordinates [ *x, f* ( *x* )] in the *xy* -plane, when *x* and *y* are numbers. A similar definition can be given for functions involving more general kinds of variables. In mathematics interest is almost exclusively in line graphs and what these reveal about the functions they represent. Statistics makes extensive use of both line graphs and bar graphs, in which the lengths of the various bars show the quantities to be compared. Graph is also a mathematical term used in combinatorics to designate a geometric object consisting of vertices and edges (joining pairs of vertices). Such objects have been studied considerably in recent years because of the applicability to such diverse fields as computer networks, game theory, and social psychology.

*The Columbia Electronic Encyclopedia,* 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

#### More on *graph* from Infoplease:

#### See more Encyclopedia articles on: Mathematics