proposition: Fact embd_node_subproof (u : ddart): node (sval u) \in bc.
proof: Proof. by rewrite inE /= -(fclosed1 rcN) [~~ _](valP u). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype path fingraph) fourcolor(hypermap geometry color chromogram coloring patch) fourcolor(snip revsnip kempe birkhoff contract)