diff options
| -rw-r--r-- | theories/Arith/Plus.v | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/theories/Arith/Plus.v b/theories/Arith/Plus.v index 98961fce8..5f7517c75 100644 --- a/theories/Arith/Plus.v +++ b/theories/Arith/Plus.v @@ -198,16 +198,14 @@ Qed. tail-recursive, whereas [plus] is not. This can be useful when extracting programs. *) -Fixpoint plus_acc q n {struct n} : nat := +Fixpoint tail_plus n m {struct n} : nat := match n with - | O => q - | S p => plus_acc (S q) p + | O => m + | S n => tail_plus n (S m) end. -Definition tail_plus n m := plus_acc m n. - Lemma plus_tail_plus : forall n m, n + m = tail_plus n m. -unfold tail_plus in |- *; induction n as [| n IHn]; simpl in |- *; auto. +induction n as [| n IHn]; simpl in |- *; auto. intro m; rewrite <- IHn; simpl in |- *; auto. Qed. |