proposition: Lemma lem_big_step_deterministic : forall c s s1, c >> s ==> s1 -> forall s2, c >> s ==> s2 -> s1 = s2.
proof: Proof. time (induction 1; sauto brefl: on). Undo. time (induction 1; sauto lazy: on brefl: on). Undo. time (induction 1; sauto lazy: on quick: on brefl: on). Qed.
imports: Hammer(Tactics Reflect) String Arith Lia