--- /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/datatypes/compare/".
+
+inductive compare :Set \def
+| LT : compare
+| EQ : compare
+| GT : compare.
+
+definition compare_invert: compare \to compare \def
+ \lambda c.
+ match c with
+ [ LT \Rightarrow GT
+ | EQ \Rightarrow EQ
+ | GT \Rightarrow LT ].