proposition: Theorem andb_true_elim2' : forall b c : bool, andb b c = true -> c = true.
proof: Proof. Admitted. Theorem andb3_exchange' : forall b c d, andb (andb b c) d = andb (andb b d) c. Proof. Admitted. Theorem app_nil_r : forall (X : Type) (lst : list X), lst ++ [] = lst. Proof. intros X lst. induction lst as [ | h t IHt]. - reflexivity. - simpl. rewrite IHt. reflexivity. Qed.
imports: Coq(Arith List) LF(IndProp) Coq(Lia)