proposition: Lemma sub_adj_icpK : {homo icpK : x y / adj x y}.
proof: Proof. by move=> x y xAy; rewrite /= adj_icpK xAy. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry color)