(** * Addendum to the standard library of Coq *)
Require Export Omega.
Global Obligation Tactic := idtac.
Notation "[ x ; .. ; y ]" := (cons x .. (cons y nil) .. ).

Lemma map_eq_hd :
forall A B (f:A->B) d l1 l2,
map f l1 = map f l2 -> f (hd d l1) = f (hd d l2).