We define a variant of the H-coloring problem where the number of preimages of certain vertices is predetermined as part of the problem input. We consider the decision and the counting version of the problem, namely the restrictive H-coloring and the restrictive #H-coloring problems, and we provide a dichotomy theorem determining the H’s for which the restrictive H-coloring problem is either NP...

Let G(V,E) be a k-uniform hypergraph. A hyperedge e ∈ E is said to be properly (r, p) colored by an r-coloring of vertices in V if e contains vertices of at least p distinct colors in the rcoloring. An r-coloring of vertices in V is called a strong (r, p) coloring if every hyperedge e∈E is properly (r, p) colored by the r-coloring. We study the maximum number of hyperedges that can be properly ...

All graph in this paper be a connected and simple graph. Let c:V(G)→{1,2,…,k} is proper vertex coloring where k ≥ 2 which induces edge c':E(G)→{1,2,…,k} define by c' (uv)=|c(u)-c(v)|, uv E(G) called graceful k-coloring. A c of G if k-coloring for some k∈ N. The minimum chromatic number denoted χ_g (G). In paper, we will investigate the establish exact value on grid family namely H 〖(H〗_n) n≥2 m...

In this paper we present a hybrid technique that applies a genetic algorithm followed by wisdom of artificial crowds approach to solving the graph-coloring problem. The genetic algorithm described here utilizes more than one parent selection and mutation methods depending on the state of fitness of its best solution. This results in shifting the solution to the global optimum more quickly than ...