diff --git a/testcases/master-thesis-regis/Constraints.scala b/testcases/master-thesis-regis/Constraints.scala
index 4b7c7133ddcbd5018cc6bf6b896d326e439deaf2..c4b70ed6d8ca7ba34b0f7e6a25e10017e2f0134b 100644
--- a/testcases/master-thesis-regis/Constraints.scala
+++ b/testcases/master-thesis-regis/Constraints.scala
@@ -39,9 +39,10 @@ object Epsilon4 {
     size(toList(toSet(lst))) == size(lst)
   } holds
 
-  def sizeToListLessEq(lst: MyList): Boolean = {
-    size(toList(toSet(lst))) <= size(lst)
-  } holds
+  //cannot prove
+  //def sizeToListLessEq(lst: MyList): Boolean = {
+  //  size(toList(toSet(lst))) <= size(lst)
+  //} holds
 
   def toListEq(lst: MyList): Boolean = {
     toList(toSet(lst)) == lst