# Coloring¶

Graph coloring is the problem of assigning a color to the vertices of a graph in a way that no adjacent vertices have the same color.

## Example¶

The map-coloring problem is to assign a color to each region of a map (represented by a vertex on a graph) such that any two regions sharing a border (represented by an edge of the graph) have different colors.

Coloring a map of Canada with four colors.

 is_vertex_coloring(G, coloring) Determines whether the given coloring is a vertex coloring of graph G. min_vertex_color(G[, sampler, chromatic_lb, …]) Returns an approximate minimum vertex coloring. min_vertex_color_qubo(G[, chromatic_lb, …]) Return a QUBO with ground states corresponding to a minimum vertex coloring. vertex_color(G, colors[, sampler]) Returns an approximate vertex coloring. vertex_color_qubo(G, colors) Return the QUBO with ground states corresponding to a vertex coloring.