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(* 02110-1301 USA                                                     *)
(* Contribution to the Coq Library   V6.3 (July 1999)                    *)
(****************************************************************)
(*           The Calculus of Inductive Constructions            *)
(*                       COQ v5.10                              *)
(*                                                              *)
(* Laurent Arditi.  Laboratoire I3S. CNRS ura 1376.             *)
(* Universite de Nice - Sophia Antipolis                        *)
(* arditi@unice.fr, http://wwwi3s.unice.fr/~arditi/lolo.html    *)
(*                                                              *)
(* date: may 1995                                               *)
(* file: Lists_compl.v                                          *)
(* contents: definitions and lemmas on polymorphic lists,       *)
(* length, append, map, reverse, list_constant                  *)
(* decidability of equality on lists *** TO BE PROVED ***       *)
(****************************************************************)
Require Export List.
Require Export Arith_compl.
Section Lists_compl.
Variable A B : Set.

Lemma length_eq2 :
forall (x : A) (l : list A), length (x :: l) = S (length l).