An application of principal bundles to coloring of graphs and hypergraphs
An interesting connection between the chromatic number of a graph and the connectivity of an associated simplicial complex , its “neighborhood complex”, was found by Lovász in 1978 (cf. [J. Comb. Theory, Ser. A 25, 319-324 (1978; Zbl 0418.05028)]). In 1986 a generalization to the chromatic number of a -uniform hypergraph , for an odd prime, using an associated simplicial complex , was found ([, and , Trans. Am. Math. Soc. 298, 359-370 (1986; Zbl 0605.05033)], Prop. 2.1). It was already...