--- a/thys/Rec_Def.thy	Fri Dec 21 15:30:24 2018 +0100
+++ b/thys/Rec_Def.thy	Mon Jan 07 13:44:19 2019 +0100
@@ -1,3 +1,8 @@
+(* Title: thys/Rec_Def.thy
+   Author: Jian Xu, Xingyuan Zhang, and Christian Urban
+   Modifications: Sebastiaan Joosten
+*)
+
 theory Rec_Def
 imports Main
 begin