(* This program is free software; you can redistribute it and/or      *)
(* modify it under the terms of the GNU Lesser General Public License *)
(* as published by the Free Software Foundation; either version 2.1   *)
(* of the License, or (at your option) any later version.             *)
(*                                                                    *)
(* This program is distributed in the hope that it will be useful,    *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of     *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the      *)
(* GNU General Public License for more details.                       *)
(*                                                                    *)
(* You should have received a copy of the GNU Lesser General Public   *)
(* License along with this program; if not, write to the Free         *)
(* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA *)
(* 02110-1301 USA                                                     *)
(* Contribution to the Coq Library   V6.3 (July 1999)                    *)
(*-- Tactics Tauto & Intuition --*)
(*-- Tauto: Tactic for automating proof in Intuionnistic Propositional Caulculus, based on the contraction-free LJT of Dickhoff Ref:   Roy Dyckhoff, The Journal of Symbolic Logic Volume 57, Number 3, Sept. 1992                                      --*)
Parameter A B C : Prop.
Parameter even : nat -> Prop.
Parameter P : nat -> Prop.
(*-- Examples of intuitionistics tautologies Ref: Lincoln Wallen, Automated Deduction in Nonclassical Logics, 1990 Sthephen Klenne, Introduction to Metamathematics,1952. --*)
tauto.
Qed.
tauto.
Qed.

(*-- Example with a first ordre formula --*)
Theorem Ex_Klenne' : forall n : nat, ~ ~ (even n \/ ~ even n).