--- a/src/HOL/Predicate_Compile_Examples/Reg_Exp_Example.thy Sat May 19 20:42:34 2018 +0200
+++ b/src/HOL/Predicate_Compile_Examples/Reg_Exp_Example.thy Sun May 20 11:57:17 2018 +0200
@@ -4,7 +4,7 @@
"HOL-Library.Code_Prolog"
begin
-text \<open>An example from the experiments from SmallCheck (\<^url>\<open>http://www.cs.york.ac.uk/fp/smallcheck\<close>)\<close>
+text \<open>An example from the experiments from SmallCheck (\<^url>\<open>https://www.cs.york.ac.uk/fp/smallcheck\<close>)\<close>
text \<open>The example (original in Haskell) was imported with Haskabelle and
manually slightly adapted.
\<close>