diff -r 08cc5ab18c84 -r aaa31cd0caef src/HOL/Data_Structures/Lookup2.thy
--- a/src/HOL/Data_Structures/Lookup2.thy	Sun Apr 08 09:46:33 2018 +0200
+++ b/src/HOL/Data_Structures/Lookup2.thy	Sun Apr 08 11:05:52 2018 +0200
@@ -6,7 +6,7 @@
 imports
   Tree2
   Cmp
-  Map_by_Ordered
+  Map_Specs
 begin
 
 fun lookup :: "('a::linorder * 'b, 'c) tree \<Rightarrow> 'a \<Rightarrow> 'b option" where