subgraph of G. A graph H can be seen to be n-colorable iff H is an interpretation of K n (the
complete graph on n vertices): hence colorability is a special case of the concept of
interpretation. In this paper the complexity of the general coloring problem, ie, of deciding for
a given graph G whether some graph H is an interpretation of G, is investigated. It is shown
that for many very simple undirected graphs G this question is NP-complete (this was …