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authorGravatar Hugo Herbelin <Hugo.Herbelin@inria.fr>2015-09-08 11:45:07 +0200
committerGravatar Hugo Herbelin <Hugo.Herbelin@inria.fr>2015-09-08 13:49:55 +0200
commit11fc2695936c4cff0eea18cb97f6c83eb7cff09d (patch)
tree3349173f6ece355c7a363bf140191f22a2e17c4f /theories/Logic/WeakFan.v
parentf2130a88e1f67d68d1062cce883a7c2666b146d8 (diff)
Minor modifications to WeakFanTheorem.
Diffstat (limited to 'theories/Logic/WeakFan.v')
-rw-r--r--theories/Logic/WeakFan.v11
1 files changed, 4 insertions, 7 deletions
diff --git a/theories/Logic/WeakFan.v b/theories/Logic/WeakFan.v
index 49cc12b85..2f84ebe5f 100644
--- a/theories/Logic/WeakFan.v
+++ b/theories/Logic/WeakFan.v
@@ -89,17 +89,14 @@ Qed.
Theorem WeakFanTheorem : forall P, barred P -> inductively_barred P [].
Proof.
intros P Hbar.
-destruct (Hbar (X P)) as (l,(Hd,HP)).
+destruct Hbar with (X P) as (l,(Hd/Y_approx,HP)).
assert (inductively_barred P l) by (apply (now P l), HP).
clear Hbar HP.
-induction l.
+induction l as [|a l].
- assumption.
- destruct Hd as (Hd,HX).
apply (IHl Hd). clear IHl.
destruct a; unfold X in HX; simpl in HX.
- + apply propagate.
- * apply H.
- * destruct HX as (l',(Hl,(HY,Ht))); firstorder.
- apply Y_approx in Hd. rewrite <- (Y_unique P l' l Hl); trivial.
- + destruct HX. exists l. split; auto using Y_approx.
+ + apply propagate; assumption.
+ + exfalso; destruct (HX H).
Qed.