Example that shows that current alpha is wrong.
--- a/Nominal/Term5.thy Mon Mar 01 07:46:50 2010 +0100
+++ b/Nominal/Term5.thy Mon Mar 01 11:40:48 2010 +0100
@@ -172,6 +172,18 @@
apply (simp add: permute_trm5_lts fresh_star_def)
done
+lemma lets_ok3:
+ "(Lt5 (Lcons x (Ap5 (Vr5 y) (Vr5 x)) (Lcons y (Vr5 y) Lnil)) (Ap5 (Vr5 x) (Vr5 y))) =
+ (Lt5 (Lcons y (Ap5 (Vr5 x) (Vr5 y)) (Lcons x (Vr5 x) Lnil)) (Ap5 (Vr5 x) (Vr5 y)))"
+apply (subst alpha5_INJ)
+apply (rule conjI)
+apply (rule_tac x="(x \<leftrightarrow> y)" in exI)
+apply (simp only: alpha_gen)
+apply (simp add: permute_trm5_lts fresh_star_def)
+apply (rule_tac x="0 :: perm" in exI)
+apply (simp only: alpha_gen)
+apply (simp add: permute_trm5_lts fresh_star_def)
+done
lemma lets_not_ok1:
"x \<noteq> y \<Longrightarrow> (Lt5 (Lcons x (Vr5 x) (Lcons y (Vr5 y) Lnil)) (Ap5 (Vr5 x) (Vr5 y))) \<noteq>