Section CGNoBadCycles.
Variable
no_bad_cycles :
forall (x : ad) (d : D) (l : list ad),
CG_path x d (x :: l) -> Dle Dz d = true.
(*s The edges are in the domain of the graph *)

Lemma CG_edge_in_cg_1 :
forall (x y : ad) (d : D),
CG_edge x y = Some d -> in_FSet x (MapDom _ cg) = true.