diff -r 0c10aeff57d7 -r e5e9a6c45597 test/Tools/isac/ADDTESTS/course/SignalProcess/Build_Inverse_Z_Transform.thy
--- a/test/Tools/isac/ADDTESTS/course/SignalProcess/Build_Inverse_Z_Transform.thy	Sat Jul 17 14:05:28 2021 +0200
+++ b/test/Tools/isac/ADDTESTS/course/SignalProcess/Build_Inverse_Z_Transform.thy	Sun Jul 18 16:20:32 2021 +0200
@@ -654,7 +654,7 @@
       of simplification occurs right here, in the next step.\<close>
 
 ML \<open>
-  Rewrite.trace_on := false;
+  Rewrite.trace_on := false; (*true false*)
   val SOME fract1 =
     parseNEW ctxt "(z - 1/2)*(z - -1/4) * (A/(z - 1/2) + B/(z - -1/4))";
   (*
@@ -1244,7 +1244,7 @@
       tree and check if every node implements that what we have wanted.\<close>
       
 ML \<open>
-  Rewrite.trace_on := false; (*true*)
+  Rewrite.trace_on := false; (*true false*)
   LItool.trace_on := false; (*true*)
   print_depth 9;