Graph coloring with cardinality constraints on the neighborhoods
Abstract
Extensions and variations of the basic problem of graph coloring are introduced. It consists essentially in finding in a graph G a k-coloring, i.e., a partition V 1, ..., V k of the vertex set of G such that for some specified neighborhood ˜N (v) of each vertex v, the number of vertices in ˜N (v) \ V i is (at most) a given integer hi v. The complexity of some variations is discussed according to ˜N (v) which may be the usual neighbors, or the vertices at distance at most 2 or the closed neighborhood of v (v and its neighbors). Polynomially solvable cases are exhibited (in particular when G is a special tree).