--- /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/bool/".
+
+inductive bool : Set \def
+ | true : bool
+ | false : bool.
+
+definition notb : bool \to bool \def
+\lambda b:bool.
+ match b with
+ [ true \Rightarrow false
+ | false \Rightarrow true ].
+
+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]
+ | false \Rightarrow false ].
+
+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 ].
+
+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].