proposition: Lemma step_coborder_ok : border step_conodes = (border (conodes c) :|: if end_node \in conodes c then set0 else end_node) :\ end_port.
proof: Proof. rewrite /step_conodes /=. destruct Bool.bool_dec => //. by rewrite Hcond /=. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup zmodp poly ssrnum) mathcomp(matrix perm) ssr_ext ssralg_ext fdist subgraph_partition tanner