# Chromatic Number

The chromatic number is the smallest number of colors necessary to color the vertices of a graph or the regions of a surface such that no two adjacent vertices or regions are the same color.

Chromatic number is a college-level concept that would be first encountered in a discrete mathematics course covering graph theory.

### Prerequisites

Graph: | In graph theory, a graph, also called a network, is a collection of points together with lines that connect some subset of the points. |