diff -r b33b42211bbf -r 188826f1ccdb Nominal/nominal_inductive.ML
--- a/Nominal/nominal_inductive.ML	Thu Mar 13 09:30:26 2014 +0000
+++ b/Nominal/nominal_inductive.ML	Mon Mar 24 15:31:17 2014 +0000
@@ -32,8 +32,8 @@
 
 (* fixme: move to nominal_library *)
 fun real_head_of (@{term Trueprop} $ t) = real_head_of t
-  | real_head_of (Const ("==>", _) $ _ $ t) = real_head_of t
-  | real_head_of (Const (@{const_name all}, _) $ Abs (_, _, t)) = real_head_of t
+  | real_head_of (Const (@{const_name Pure.imp}, _) $ _ $ t) = real_head_of t
+  | real_head_of (Const (@{const_name Pure.all}, _) $ Abs (_, _, t)) = real_head_of t
   | real_head_of (Const (@{const_name All}, _) $ Abs (_, _, t)) = real_head_of t
   | real_head_of (Const ("HOL.induct_forall", _) $ Abs (_, _, t)) = real_head_of t
   | real_head_of t = head_of t