diff -r 5b01f7c233f8 -r a33d3040bf7e Attic/MyInduction.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Attic/MyInduction.thy	Fri Feb 05 10:16:10 2016 +0000
@@ -0,0 +1,19 @@
+theory MyInduction
+imports Main
+begin
+
+fun itrev :: "'a list \<Rightarrow> 'a list \<Rightarrow> 'a list" where
+"itrev [] ys = ys" |
+"itrev (x#xs) ys = itrev xs (x#ys)"
+
+lemma "itrev xs [] = rev xs"
+apply(induction xs)
+apply(auto)
+oops
+
+lemma "itrev xs ys = rev xs @ ys"
+apply(induction xs arbitrary: ys)
+apply auto
+done
+
+