src/CTT/CTT.thy

--- a/src/CTT/CTT.thy	Thu Jan 11 12:32:07 2018 +0100
+++ b/src/CTT/CTT.thy	Thu Jan 11 13:48:17 2018 +0100
@@ -434,7 +434,7 @@
 
 (*0 subgoals vs 1 or more*)
 val (safe0_brls, safep_brls) =
-    List.partition (curry (=) 0 o subgoals_of_brl) safe_brls
+    List.partition (curry (op =) 0 o subgoals_of_brl) safe_brls
 
 fun safestep_tac ctxt thms i =
     form_tac ctxt ORELSE