+++ /dev/null
-(**************************************************************************)
-(* __ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| A.Asperti, C.Sacerdoti Coen, *)
-(* ||A|| E.Tassi, S.Zacchiroli *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU Lesser General Public License Version 2.1 *)
-(* *)
-(**************************************************************************)
-
-set "baseuri" "cic:/matita/library_auto/nat/times".
-
-include "nat/plus.ma".
-
-let rec times n m \def
- match n with
- [ O \Rightarrow O
- | (S p) \Rightarrow m+(times p m) ].
-
-(*CSC: the URI must disappear: there is a bug now *)
-interpretation "natural times" 'times x y = (cic:/matita/library_auto/nat/times/times.con x y).
-
-theorem times_n_O: \forall n:nat. O = n*O.
-intros.elim n
-[ auto
- (*simplify.
- reflexivity.*)
-| simplify. (* qui auto non funziona: Uncaught exception: Invalid_argument ("List.map2")*)
- assumption.
-]
-qed.
-
-theorem times_n_Sm :
-\forall n,m:nat. n+(n*m) = n*(S m).
-intros.elim n
-[ auto.
- (*simplify.reflexivity.*)
-| simplify.
- auto
- (*apply eq_f.
- rewrite < H.
- transitivity ((n1+m)+n1*m)
- [ symmetry.
- apply assoc_plus.
- | transitivity ((m+n1)+n1*m)
- [ apply eq_f2.
- apply sym_plus.
- reflexivity.
- | apply assoc_plus.
- ]
- ]*)
-]
-qed.
-
-(* NOTA:
- se non avessi semplificato con auto tutto il secondo ramo della tattica
- elim n, avrei comunque potuto risolvere direttamente con auto entrambi
- i rami generati dalla prima applicazione della tattica transitivity
- (precisamente transitivity ((n1+m)+n1*m)
- *)
-
-theorem times_n_SO : \forall n:nat. n = n * S O.
-intros.
-rewrite < times_n_Sm.
-auto paramodulation. (*termina la dim anche solo con auto*)
-(*rewrite < times_n_O.
-rewrite < plus_n_O.
-reflexivity.*)
-qed.
-
-theorem times_SSO_n : \forall n:nat. n + n = S (S O) * n.
-intros.
-simplify.
-auto paramodulation. (* termina la dim anche solo con auto*)
-(*rewrite < plus_n_O.
-reflexivity.*)
-qed.
-
-theorem symmetric_times : symmetric nat times.
-unfold symmetric.
-intros.elim x
-[ auto
- (*simplify.apply times_n_O.*)
-| simplify.
- auto
- (*rewrite > H.apply times_n_Sm.*)
-]
-qed.
-
-variant sym_times : \forall n,m:nat. n*m = m*n \def
-symmetric_times.
-
-theorem distributive_times_plus : distributive nat times plus.
-unfold distributive.
-intros.elim x;simplify
-[ reflexivity.
-| auto
- (*rewrite > H.
- rewrite > assoc_plus.
- rewrite > assoc_plus.
- apply eq_f.
- rewrite < assoc_plus.
- rewrite < (sym_plus ? z).
- rewrite > assoc_plus.
- reflexivity.*)
-]
-qed.
-
-variant distr_times_plus: \forall n,m,p:nat. n*(m+p) = n*m + n*p
-\def distributive_times_plus.
-
-theorem associative_times: associative nat times.
-unfold associative.intros.
-elim x;simplify
-[ apply refl_eq
-| auto
- (*rewrite < sym_times.
- rewrite > distr_times_plus.
- rewrite < sym_times.
- rewrite < (sym_times (times n y) z).
- rewrite < H.
- apply refl_eq.*)
-]
-qed.
-
-variant assoc_times: \forall n,m,p:nat. (n*m)*p = n*(m*p) \def
-associative_times.