--- a/src/HOL/ex/Quickcheck_Examples.thy Tue Dec 20 17:40:15 2011 +0100
+++ b/src/HOL/ex/Quickcheck_Examples.thy Tue Dec 20 17:40:17 2011 +0100
@@ -6,7 +6,7 @@
header {* Examples for the 'quickcheck' command *}
theory Quickcheck_Examples
-imports Complex_Main
+imports Complex_Main "~~/src/HOL/Library/Dlist"
begin
text {*
@@ -342,6 +342,17 @@
quickcheck[expect = counterexample]
oops
+subsection {* Examples with abstract types *}
+
+lemma
+ "Dlist.length (Dlist.remove x xs) = Dlist.length xs - 1"
+quickcheck[exhaustive]
+oops
+
+lemma
+ "Dlist.length (Dlist.insert x xs) = Dlist.length xs + 1"
+quickcheck[exhaustive]
+oops
subsection {* Examples with Records *}