proposition: Lemma reachable_n_maybe_reachable {M n X Y} : reachable_n M n X Y-> maybe_reachable M n X Y.
proof: Proof. move=> ?. by left. Qed.
imports: List Lia Relation_Operators Undecidability.StackMachines.Util(Nat_facts List_facts) Undecidability.StackMachines.Reductions.CM1_HALT_to_SMNdl_UB.SMX ssreflect ssrbool ssrfun