X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fmatita%2Flibrary%2Fdatatypes%2Fbool.ma;h=3292e6789610f6114c590be58d18c729a3bf92fe;hb=4167cea65ca58897d1a3dbb81ff95de5074700cc;hp=fdb376c605b80b54d4d1a5f8a612aaf8c714f454;hpb=244d65f63ca6a736b871f9f91328fe8c5524ff05;p=helm.git

diff --git a/helm/matita/library/datatypes/bool.ma b/helm/matita/library/datatypes/bool.ma
index fdb376c60..3292e6789 100644
--- a/helm/matita/library/datatypes/bool.ma
+++ b/helm/matita/library/datatypes/bool.ma
@@ -12,34 +12,115 @@
 (*                                                                        *)
 (**************************************************************************)
 
-set "baseuri" "cic:/matita/bool/".
+set "baseuri" "cic:/matita/datatypes/bool/".
+
+include "logic/equality.ma".
 
 inductive bool : Set \def 
   | true : bool
   | false : bool.
 
+theorem bool_elim: \forall P:bool \to Prop. \forall b:bool.
+  (b = true \to P true)
+  \to (b = false \to P false)
+  \to P b.
+  intros 2 (P b).
+  elim b;
+  [ apply H; reflexivity
+  | apply H1; reflexivity
+  ]
+qed.
+
+theorem not_eq_true_false : true \neq false.
+unfold Not.intro.
+change with 
+match true with
+[ true \Rightarrow False
+| flase \Rightarrow True].
+rewrite > H.simplify.exact I.
+qed.
+
 definition notb : bool \to bool \def
 \lambda b:bool. 
  match b with 
  [ true \Rightarrow false
  | false \Rightarrow true ].
+ 
+theorem notb_elim: \forall b:bool.\forall P:bool \to Prop.
+match b with
+[ true \Rightarrow P false
+| false \Rightarrow P true] \to P (notb b).
+intros 2.elim b.exact H. exact H.
+qed.
+
+(*CSC: the URI must disappear: there is a bug now *)
+interpretation "boolean not" 'not x = (cic:/matita/datatypes/bool/notb.con x).
 
 definition andb : bool \to bool \to bool\def
 \lambda b1,b2:bool. 
  match b1 with 
- [ true \Rightarrow 
-	match b2 with [true \Rightarrow true | false \Rightarrow false]
+ [ true \Rightarrow b2
  | false \Rightarrow false ].
 
+(*CSC: the URI must disappear: there is a bug now *)
+interpretation "boolean and" 'and x y = (cic:/matita/datatypes/bool/andb.con x y).
+
+theorem andb_elim: \forall b1,b2:bool. \forall P:bool \to Prop.
+match b1 with
+[ true \Rightarrow P b2
+| false \Rightarrow P false] \to P (b1 \land b2).
+intros 3.elim b1.exact H. exact H.
+qed.
+
+theorem andb_true_true: \forall b1,b2. (b1 \land b2) = true \to b1 = true.
+intro. elim b1.
+reflexivity.
+assumption.
+qed.
+
 definition orb : bool \to bool \to bool\def
 \lambda b1,b2:bool. 
  match b1 with 
- [ true \Rightarrow 
-	match b2 with [true \Rightarrow true | false \Rightarrow false]
- | false \Rightarrow false ].
+ [ true \Rightarrow true
+ | false \Rightarrow b2].
+
+theorem orb_elim: \forall b1,b2:bool. \forall P:bool \to Prop.
+match b1 with
+[ true \Rightarrow P true
+| false \Rightarrow P b2] \to P (orb b1 b2).
+intros 3.elim b1.exact H. exact H.
+qed.
+
+(*CSC: the URI must disappear: there is a bug now *)
+interpretation "boolean or" 'or x y = (cic:/matita/datatypes/bool/orb.con x y).
 
 definition if_then_else : bool \to Prop \to Prop \to Prop \def 
 \lambda b:bool.\lambda P,Q:Prop.
 match b with
 [ true \Rightarrow P
 | false  \Rightarrow Q].
+
+(*CSC: missing notation for if_then_else *)
+
+theorem bool_to_decidable_eq:
+ \forall b1,b2:bool. decidable (b1=b2).
+ intros.
+ unfold decidable.
+ elim b1.
+  elim b2.
+   left. reflexivity.
+   right. exact not_eq_true_false.
+  elim b2.
+   right. unfold Not. intro.
+   apply not_eq_true_false.
+   symmetry. exact H.
+   left. reflexivity.
+qed.
+
+theorem P_x_to_P_x_to_eq:
+ \forall A:Set. \forall P: A \to bool.
+  \forall x:A. \forall p1,p2:P x = true. p1 = p2.
+ intros.
+ apply eq_to_eq_to_eq_p_q.
+ exact bool_to_decidable_eq.
+qed.