diff -r 991ecdd985d9 -r 02cf78f0afce doc-src/TutorialI/Inductive/AB.thy
--- a/doc-src/TutorialI/Inductive/AB.thy	Tue Jun 28 12:32:38 2005 +0200
+++ b/doc-src/TutorialI/Inductive/AB.thy	Tue Jun 28 15:26:32 2005 +0200
@@ -133,8 +133,8 @@
 *}
 
 apply(induct_tac w)
- apply(simp)
-by(force simp add: zabs_def take_Cons split: nat.split if_splits)
+apply(auto simp add: abs_if take_Cons split: nat.split)
+done
 
 text{*
 Finally we come to the above-mentioned lemma about cutting in half a word with two more elements of one sort than of the other sort: