proposition: Lemma bound_try_step_shape {y l r} : SMX.step M (l, r, '?|) y -> ((l = [§1] ++ skipn 1 l) \/ (l = [§0] ++ [§1] ++ skipn 2 l) \/ (l = [§0] ++ [§0] ++ skipn 2 l)) /\ (r = [§1] ++ skipn 1 r).
proof: Proof. move /stepE => [] > [] *; subst; firstorder done. Qed.
imports: Relation_Operators Operators_Properties Lia PeanoNat List Undecidability.StackMachines.Reductions.CM1_HALT_to_SMNdl_UB.SMX_facts Undecidability.StackMachines.Util(Nat_facts List_facts) ssreflect ssrbool ssrfun