--- a/src/HOL/Data_Structures/Tree23_Set.thy Sun Apr 08 09:46:33 2018 +0200
+++ b/src/HOL/Data_Structures/Tree23_Set.thy Sun Apr 08 11:05:52 2018 +0200
@@ -6,7 +6,7 @@
imports
Tree23
Cmp
- Set_Interfaces
+ Set_Specs
begin
fun isin :: "'a::linorder tree23 \<Rightarrow> 'a \<Rightarrow> bool" where