--- a/src/Doc/Datatypes/Datatypes.thy Tue May 13 11:10:23 2014 +0200
+++ b/src/Doc/Datatypes/Datatypes.thy Tue May 13 11:10:23 2014 +0200
@@ -1531,7 +1531,7 @@
text {*
Noncorecursive codatatypes coincide with the corresponding datatypes, so they
-are useless in practice. \emph{Corecursive codatatypes} have the same syntax
+are rarely used in practice. \emph{Corecursive codatatypes} have the same syntax
as recursive datatypes, except for the command name. For example, here is the
definition of lazy lists:
*}