proposition: Fact gcompr_edge_subproof v : predC (gcomp z) (edge (val v)).
proof: Proof. by rewrite /= -(glink1r (glinkE _)) (valP v). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry jordan color coloring)