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diff --git a/plugins/subtac/test/wf.v b/plugins/subtac/test/wf.v
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+Notation "( x & y )" := (@existS _ _ x y) : core_scope.
+Unset Printing All.
+Require Import Coq.Arith.Compare_dec.
+
+Require Import Coq.subtac.Utils.
+
+Ltac one_simpl_hyp :=
+ match goal with
+ | [H : (`exist _ _ _) = _ |- _] => simpl in H
+ | [H : _ = (`exist _ _ _) |- _] => simpl in H
+ | [H : (`exist _ _ _) < _ |- _] => simpl in H
+ | [H : _ < (`exist _ _ _) |- _] => simpl in H
+ | [H : (`exist _ _ _) <= _ |- _] => simpl in H
+ | [H : _ <= (`exist _ _ _) |- _] => simpl in H
+ | [H : (`exist _ _ _) > _ |- _] => simpl in H
+ | [H : _ > (`exist _ _ _) |- _] => simpl in H
+ | [H : (`exist _ _ _) >= _ |- _] => simpl in H
+ | [H : _ >= (`exist _ _ _) |- _] => simpl in H
+ end.
+
+Ltac one_simpl_subtac :=
+  destruct_exists ;
+  repeat one_simpl_hyp ; simpl.
+
+Ltac simpl_subtac :=  do 3 one_simpl_subtac ; simpl.
+
+Require Import Omega.
+Require Import Wf_nat.
+
+Program Fixpoint euclid (a : nat) (b : { b : nat | b <> O }) {wf a lt}  :
+  { q : nat & { r : nat | a = b * q + r /\ r < b } } :=
+  if le_lt_dec b a then let (q', r) := euclid (a - b) b in
+  (S q' & r)
+  else (O & a).
+destruct b ; simpl_subtac.
+omega.
+simpl_subtac.
+assert(x0 * S q' = x0 + x0 * q').
+rewrite <- mult_n_Sm.
+omega.
+rewrite H2 ; omega.
+simpl_subtac.
+split ; auto with arith.
+omega.
+apply lt_wf.
+Defined.
+
+Check euclid_evars_proof.
+\ No newline at end of file