fact: Record invariants (e : env) := Invariants { inv_wf_color : wf_color e; inv_wf_num : wf_num e; inv_wf_graph : wf_graph e; wf_noblack_towhite : noblack_to_white e; inv_sccs : esccs e = black_gsccs e; }.
imports: mathcomp(all_ssreflect) bigmin extra