Further hardness results on the rainbow vertex-connection number of graphs
arXiv:1110.1915
Abstract
A vertex-colored graph is {\it rainbow vertex-connected} if any pair of vertices in are connected by a path whose internal vertices have distinct colors, which was introduced by Krivelevich and Yuster. The {\it rainbow vertex-connection number} of a connected graph , denoted by , is the smallest number of colors that are needed in order to make rainbow vertex-connected. In a previous paper we showed that it is NP-Complete to decide whether a given graph has . In this paper we show that for every integer , deciding whether is NP-Hard. We also show that for any fixed integer , this problem belongs to NP-class, and so it becomes NP-Complete.
10 pages