\forall z. if_then_else (OZ_testb z) (eq Z z OZ) (Not (eq Z z OZ)).
intros.elim z.simplify.reflexivity.
simplify.intros.
-cut match neg e with
+cut match neg e1 with
[ OZ \Rightarrow True
| (pos n) \Rightarrow False
| (neg n) \Rightarrow False].
apply Hcut.rewrite > H.simplify.exact I.
simplify.intros.
-cut match pos e with
+cut match pos e2 with
[ OZ \Rightarrow True
| (pos n) \Rightarrow False
| (neg n) \Rightarrow False].
theorem Zpred_succ: \forall z:Z. eq Z (Zpred (Zsucc z)) z.
intros.elim z.reflexivity.
-elim e.reflexivity.
+elim e1.reflexivity.
reflexivity.
reflexivity.
qed.
theorem Zsucc_pred: \forall z:Z. eq Z (Zsucc (Zpred z)) z.
intros.elim z.reflexivity.
reflexivity.
-elim e.reflexivity.
+elim e2.reflexivity.
reflexivity.
qed.
simplify.
rewrite < (sym_plus e e1).reflexivity.
simplify.
-rewrite > nat_compare_invert e e1.
-simplify.elim nat_compare e1 e.simplify.reflexivity.
+rewrite > nat_compare_invert e1 e2.
+simplify.elim nat_compare e2 e1.simplify.reflexivity.
simplify. reflexivity.
simplify. reflexivity.
elim y.simplify.reflexivity.
-simplify.rewrite > nat_compare_invert e e1.
-simplify.elim nat_compare e1 e.simplify.reflexivity.
+simplify.rewrite > nat_compare_invert e1 e2.
+simplify.elim nat_compare e2 e1.simplify.reflexivity.
simplify. reflexivity.
simplify. reflexivity.
-simplify.elim (sym_plus e1 e).reflexivity.
+simplify.elim (sym_plus e2 e).reflexivity.
qed.
theorem Zpred_neg : \forall z:Z. eq Z (Zpred z) (Zplus (neg O) z).
intros.elim z.
simplify.reflexivity.
simplify.reflexivity.
-elim e.simplify.reflexivity.
+elim e2.simplify.reflexivity.
simplify.reflexivity.
qed.
theorem Zsucc_pos : \forall z:Z. eq Z (Zsucc z) (Zplus (pos O) z).
intros.elim z.
simplify.reflexivity.
-elim e.simplify.reflexivity.
+elim e1.simplify.reflexivity.
simplify.reflexivity.
simplify.reflexivity.
qed.
simplify.reflexivity.
elim m.
simplify.
-rewrite < plus_n_O e.reflexivity.
+rewrite < plus_n_O e1.reflexivity.
simplify.
-rewrite < plus_n_Sm e e1.reflexivity.
+rewrite < plus_n_Sm e1 e.reflexivity.
qed.
theorem Zplus_succ_pred_pn :
simplify.reflexivity.
simplify.reflexivity.
elim m.
-simplify.rewrite < plus_n_Sm e O.reflexivity.
-simplify.rewrite > plus_n_Sm e (S e1).reflexivity.
+simplify.rewrite < plus_n_Sm e1 O.reflexivity.
+simplify.rewrite > plus_n_Sm e1 (S e).reflexivity.
qed.
-(*CSC: da qui in avanti rewrite ancora non utilizzata *)
+(* da qui in avanti rewrite ancora non utilizzata *)
+
theorem Zplus_succ_pred:
\forall x,y. eq Z (Zplus x y) (Zplus (Zsucc x) (Zpred y)).
intros.
(\lambda n,m. eq Z (Zplus (Zsucc (pos n)) (neg m)) (Zsucc (Zplus (pos n) (neg m)))).intro.
intros.elim n1.
simplify. reflexivity.
-elim e.simplify. reflexivity.
+elim e1.simplify. reflexivity.
simplify. reflexivity.
intros. elim n1.
simplify. reflexivity.
(\lambda n,m. eq Z (Zplus (Zsucc (neg n)) (neg m)) (Zsucc (Zplus (neg n) (neg m)))).intro.
intros.elim n1.
simplify. reflexivity.
-elim e.simplify. reflexivity.
+elim e1.simplify. reflexivity.
simplify. reflexivity.
intros. elim n1.
simplify. reflexivity.
(\lambda n,m. eq Z (Zplus (Zsucc (neg n)) (pos m)) (Zsucc (Zplus (neg n) (pos m)))).
intros.elim n1.
simplify. reflexivity.
-elim e.simplify. reflexivity.
+elim e1.simplify. reflexivity.
simplify. reflexivity.
intros. elim n1.
simplify. reflexivity.
theorem assoc_Zplus :
\forall x,y,z:Z. eq Z (Zplus x (Zplus y z)) (Zplus (Zplus x y) z).
intros.elim x.simplify.reflexivity.
-elim e.elim (Zpred_neg (Zplus y z)).
+elim e1.elim (Zpred_neg (Zplus y z)).
elim (Zpred_neg y).
elim (Zpred_plus ? ?).
reflexivity.
-elim (sym_eq ? ? ? (Zpred_plus (neg e1) ?)).
-elim (sym_eq ? ? ? (Zpred_plus (neg e1) ?)).
-elim (sym_eq ? ? ? (Zpred_plus (Zplus (neg e1) y) ?)).
+elim (sym_eq ? ? ? (Zpred_plus (neg e) ?)).
+elim (sym_eq ? ? ? (Zpred_plus (neg e) ?)).
+elim (sym_eq ? ? ? (Zpred_plus (Zplus (neg e) y) ?)).
apply f_equal.assumption.
-elim e.elim (Zsucc_pos ?).
+elim e2.elim (Zsucc_pos ?).
elim (Zsucc_pos ?).
apply (sym_eq ? ? ? (Zsucc_plus ? ?)) .
elim (sym_eq ? ? ? (Zsucc_plus (pos e1) ?)).
\forall n,m:nat. eq nat (plus n (times n m)) (times n (S m)).
intros.elim n.simplify.reflexivity.
simplify.apply f_equal.rewrite < H.
-transitivity (plus (plus e m) (times e m)).symmetry.
-apply assoc_plus.transitivity (plus (plus m e) (times e m)).
+transitivity (plus (plus e1 m) (times e1 m)).symmetry.
+apply assoc_plus.transitivity (plus (plus m e1) (times e1 m)).
apply f_equal2.
apply sym_plus.reflexivity.apply assoc_plus.
qed.
theorem le_Sn_n : \forall n:nat. Not (le (S n) n).
intros.elim n.apply le_Sn_O.simplify.intros.
-cut le (S e) e.apply H.assumption.apply le_S_n.assumption.
+cut le (S e1) e1.apply H.assumption.apply le_S_n.assumption.
qed.
theorem le_antisym : \forall n,m:nat. (le n m) \to (le m n) \to (eq nat n m).