CONTRIBUTORS

--- a/CONTRIBUTORS	Wed Nov 25 21:13:45 2020 +0100
+++ b/CONTRIBUTORS	Thu Nov 26 14:53:38 2020 +0100
@@ -5,6 +5,8 @@
 
 Contributions to this Isabelle version
 --------------------------------------
+* November 2020: Stepan Holub
+  Removed preconditions from lemma comm_append_are_replicate
 
 * November 2020: Florian Haftmann
   Bundle mixins for locale and class expressions.