Section Permutation_properties.
Variable A:Type.
Implicit Types a b : A.
Implicit Types l m : list A.
(** Compatibility with others operations on lists *)
Global Instance Permutation_in' :
Proper (Logic.eq ==> @Permutation A ==> iff) (@In A) | 10.

Lemma Permutation_app_head : forall (l tl tl' : list A),
Permutation tl tl' -> Permutation (l++tl) (l++tl').