A graph $G$ is Ramsey for a $H$ if every colouring of the edges in two colours contains monochromatic copy $H$. Two graphs $H_1$ and $H_2$ are equivalent any only it $H_2$. parameter $s$ distinguishing $s(H_1)\neq s(H_2)$ implies that not equivalent. In this paper we show chromatic number parameter. We also extend to multi-colour case use similar idea find another which distinguishing.

We study the hat chromatic number of a graph defined in following way: there is one player at each vertex G , an adversary places K colors on head player, two players can see other's hats if and only they are adjacent vertices. All simultaneously try to guess color their hat. The cannot communicate but collectively determine strategy before placed. number, denoted by HG ( ) largest such that ab...