proposition: Fact gcompd_edge_subproof u : gcomp z (edge (val u)).
proof: Proof. exact: connect_trans (valP u) (connect1 (glinkE _)). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry jordan color coloring)