--- a/thys/Positions.thy	Mon Feb 11 23:18:05 2019 +0000
+++ b/thys/Positions.thy	Sun Feb 17 22:15:06 2019 +0000
@@ -1,8 +1,10 @@
    
 theory Positions
-  imports "Spec" "Lexer" 
+  imports "Spec" "Lexer"
 begin
 
+chapter {* An alternative definition for POSIX values *}
+
 section {* Positions in Values *}
 
 fun