X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Fbasics%2Flogic.ma;h=8f981d46924556ee885407a1320d147ef07aaad0;hb=910b8e95135bfabb852c2e6d918ff50bdcb98d0a;hp=b090a8de8fc80136a2b6523ce8cc6b6cad09dd30;hpb=8ea6d456f9e71babcf5adb2caee6ddd2b95047fb;p=helm.git

diff --git a/matita/matita/lib/basics/logic.ma b/matita/matita/lib/basics/logic.ma
index b090a8de8..8f981d469 100644
--- a/matita/matita/lib/basics/logic.ma
+++ b/matita/matita/lib/basics/logic.ma
@@ -1,4 +1,4 @@
-(*
+ (*
     ||M||  This file is part of HELM, an Hypertextual, Electronic        
     ||A||  Library of Mathematics, developed at the Computer Science     
     ||T||  Department of the University of Bologna, Italy.                     
@@ -14,14 +14,14 @@ include "hints_declaration.ma".
 
 (* propositional equality *)
 
-inductive eq (A:Type[1]) (x:A) : A → Prop ≝
+inductive eq (A:Type[2]) (x:A) : A → Prop ≝
     refl: eq A x x. 
     
 interpretation "leibnitz's equality" 'eq t x y = (eq t x y).
 interpretation "leibniz reflexivity" 'refl = refl.
 
 lemma eq_rect_r:
- ∀A.∀a,x.∀p:eq ? x a.∀P: ∀x:A. eq ? x a → Type[2]. P a (refl A a) → P x p.
+ ∀A.∀a,x.∀p:eq ? x a.∀P: ∀x:A. eq ? x a → Type[3]. P a (refl A a) → P x p.
  #A #a #x #p (cases p) // qed.
 
 lemma eq_ind_r :
@@ -30,21 +30,31 @@ lemma eq_ind_r :
 
 lemma eq_rect_Type0_r:
   ∀A.∀a.∀P: ∀x:A. eq ? x a → Type[0]. P a (refl A a) → ∀x.∀p:eq ? x a.P x p.
-  #A #a #P #H #x #p (generalize in match H) (generalize in match P)
+  #A #a #P #H #x #p lapply H lapply P
   cases p; //; qed.
-  
+
+lemma eq_rect_Type1_r:
+  ∀A.∀a.∀P: ∀x:A. eq ? x a → Type[1]. P a (refl A a) → ∀x.∀p:eq ? x a.P x p.
+  #A #a #P #H #x #p lapply H lapply P
+  cases p; //; qed.
+
 lemma eq_rect_Type2_r:
   ∀A.∀a.∀P: ∀x:A. eq ? x a → Type[2]. P a (refl A a) → ∀x.∀p:eq ? x a.P x p.
-  #A #a #P #H #x #p (generalize in match H) (generalize in match P)
+  #A #a #P #H #x #p lapply H lapply P
+  cases p; //; qed.
+
+lemma eq_rect_Type3_r:
+  ∀A.∀a.∀P: ∀x:A. eq ? x a → Type[3]. P a (refl A a) → ∀x.∀p:eq ? x a.P x p.
+  #A #a #P #H #x #p lapply H lapply P
   cases p; //; qed.
 
-theorem rewrite_l: ∀A:Type[1].∀x.∀P:A → Type[1]. P x → ∀y. x = y → P y.
+theorem rewrite_l: ∀A:Type[2].∀x.∀P:A → Type[2]. P x → ∀y. x = y → P y.
 #A #x #P #Hx #y #Heq (cases Heq); //; qed.
 
 theorem sym_eq: ∀A.∀x,y:A. x = y → y = x.
-#A #x #y #Heq @(rewrite_l A x (λz.z=x)); //; qed.
+#A #x #y #Heq @(rewrite_l A x (λz.z=x)) // qed.
 
-theorem rewrite_r: ∀A:Type[1].∀x.∀P:A → Type[1]. P x → ∀y. y = x → P y.
+theorem rewrite_r: ∀A:Type[2].∀x.∀P:A → Type[2]. P x → ∀y. y = x → P y.
 #A #x #P #Hx #y #Heq (cases (sym_eq ? ? ? Heq)); //; qed.
 
 theorem eq_coerc: ∀A,B:Type[0].A→(A=B)→B.
@@ -143,7 +153,28 @@ inductive ex2 (A:Type[0]) (P,Q:A →Prop) : Prop ≝
 definition iff :=
  λ A,B. (A → B) ∧ (B → A).
 
-interpretation "iff" 'iff a b = (iff a b).  
+interpretation "iff" 'iff a b = (iff a b).
+
+lemma iff_sym: ∀A,B. A ↔ B → B ↔ A.
+#A #B * /3/ qed.
+
+lemma iff_trans:∀A,B,C. A ↔ B → B ↔ C → A ↔ C.
+#A #B #C * #H1 #H2 * #H3 #H4 % /3/ qed.
+
+lemma iff_not: ∀A,B. A ↔ B → ¬A ↔ ¬B.
+#A #B * #H1 #H2 % /3/ qed.
+
+lemma iff_and_l: ∀A,B,C. A ↔ B → C ∧ A ↔ C ∧ B.
+#A #B #C * #H1 #H2 % * /3/ qed.  
+
+lemma iff_and_r: ∀A,B,C. A ↔ B → A ∧ C ↔ B ∧ C.
+#A #B #C * #H1 #H2 % * /3/ qed.  
+
+lemma iff_or_l: ∀A,B,C. A ↔ B → C ∨ A ↔ C ∨ B.
+#A #B #C * #H1 #H2 % * /3/ qed.  
+
+lemma iff_or_r: ∀A,B,C. A ↔ B → A ∨ C ↔ B ∨ C.
+#A #B #C * #H1 #H2 % * /3/ qed.  
 
 (* cose per destruct: da rivedere *) 
 
@@ -236,6 +267,6 @@ example lemmaK : ∀A.∀x:A.∀h:x=x. eqProp ? h (refl A x).
 #A #x #h @(refl ? h: eqProp ? ? ?).
 qed.
 
-theorem streicherK : ∀T:Type[1].∀t:T.∀P:t = t → Type[2].P (refl ? t) → ∀p.P p.
- #T #t #P #H #p >(lemmaK ?? p) @H
+theorem streicherK : ∀T:Type[2].∀t:T.∀P:t = t → Type[3].P (refl ? t) → ∀p.P p.
+ #T #t #P #H #p >(lemmaK T t p) @H
 qed.