c = chromaticNumber H
Returns the chromatic number, the smallest number of colors needed to color the vertices of a graph. This method is based upon a result of FranciscoHaVan Tuyl that relates the chromatic number to an ideal membership problem.







This method should not be used with a hypergraph that has an edge of cardinality one since no coloring is possible.
The object chromaticNumber is a method function.