diff options
Diffstat (limited to 'theories/Lists/List.v')
| -rw-r--r-- | theories/Lists/List.v | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/theories/Lists/List.v b/theories/Lists/List.v index 3cba090f..ea07a849 100644 --- a/theories/Lists/List.v +++ b/theories/Lists/List.v @@ -1014,11 +1014,17 @@ Proof. 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. + Lemma map_ext : forall (A B : Type)(f g:A->B), (forall a, f a = g a) -> forall l, map f l = map g l. Proof. - induction l; simpl; auto. - rewrite H; rewrite IHl; auto. + intros; apply map_ext_in; auto. Qed. |