The Reduced Genus of a Multigraph
Résumé
We define here the reduced genus of a multigraph as the minimum genus of a hypergraph having the same adjacencies with the same multiplicities. Through a study of embedded hypergraphs, we obtain new bounds on the coloring number, clique number and point arboricity of simple graphs of a given reduced genus. We present some new related problems on graph coloring and graph representation.