diff options
Diffstat (limited to 'theories/Lists')
| -rw-r--r-- | theories/Lists/List.v | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/theories/Lists/List.v b/theories/Lists/List.v index 3cba090f3..00406f57d 100644 --- a/theories/Lists/List.v +++ b/theories/Lists/List.v @@ -1021,6 +1021,13 @@ Proof. rewrite H; rewrite IHl; auto. Qed. +Lemma map_ext_in : + forall (A B : Type)(f g:A->B) l, (forall a, In a l -> f a = g a) -> map f l = map g l. +Proof. + induction l; simpl; auto. + intros; rewrite H by intuition; rewrite IHl; auto. +Qed. + (************************************) (** Left-to-right iterator on lists *) |