diff options
| -rw-r--r-- | theories/Lists/List.v | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/theories/Lists/List.v b/theories/Lists/List.v index 69375f4a8d..7296d07ec3 100644 --- a/theories/Lists/List.v +++ b/theories/Lists/List.v @@ -827,22 +827,11 @@ Section ListOps. Hypothesis eq_dec : forall (x y : A), {x = y}+{x <> y}. - Lemma list_eq_dec : - forall l l':list A, {l = l'} + {l <> l'}. - Proof. - induction l as [| x l IHl]; destruct l' as [| y l']. - left; trivial. - right; apply nil_cons. - right; unfold not; intro HF; apply (nil_cons (sym_eq HF)). - destruct (eq_dec x y) as [xeqy|xneqy]; destruct (IHl l') as [leql'|lneql']; - try (right; unfold not; intro HF; injection HF; intros; contradiction). - rewrite xeqy; rewrite leql'; left; trivial. - Qed. - + Lemma list_eq_dec : forall l l':list A, {l = l'} + {l <> l'}. + Proof. decide equality. Defined. End ListOps. - (***************************************************) (** * Applying functions to the elements of a list *) (***************************************************) |