diff --git a/src/lib/CoAlgFormula.ml b/src/lib/CoAlgFormula.ml
index 3eff8863d9829a3320a4dd4c5a31a20b46079908..8d50b9a357a3517302baf67122cf8a10eacb16a6 100644
--- a/src/lib/CoAlgFormula.ml
+++ b/src/lib/CoAlgFormula.ml
@@ -243,28 +243,29 @@ let convertToGML formula = (* tries to convert a formula to a pure GML formula *
 let gensym = Stream.from (fun i -> Some (Printf.sprintf "#gensym%x#" i))
 
 let convertToMu formula =
+  let name = Stream.next gensym in
   let helper formula =
     match formula with
     | AF f1 ->
-       MU ("#CTL#", (OR (f1, (AX ("", (VAR "#CTL#"))))))
+       MU (name, (OR (f1, (AX ("", (VAR name))))))
     | EF f1 ->
-       MU ("#CTL#", (OR (f1, (EX ("", (VAR "#CTL#"))))))
+       MU (name, (OR (f1, (EX ("", (VAR name))))))
     | AG f1 ->
-       NU ("#CTL#", (AND (f1, (AX ("", (VAR "#CTL#"))))))
+       NU (name, (AND (f1, (AX ("", (VAR name))))))
     | EG f1 ->
-       NU ("#CTL#", (AND (f1, (EX ("", (VAR "#CTL#"))))))
+       NU (name, (AND (f1, (EX ("", (VAR name))))))
     | AU (f1, f2) ->
-       MU ("#CTL#", (OR (f2, (AND (f1, (AX ("", (VAR "#CTL#"))))))))
+       MU (name, (OR (f2, (AND (f1, (AX ("", (VAR name))))))))
     | EU (f1, f2) ->
-       MU ("#CTL#", (OR (f2, (AND (f1, (EX ("", (VAR "#CTL#"))))))))
+       MU (name, (OR (f2, (AND (f1, (EX ("", (VAR name))))))))
     | AR (f1, f2) ->
-       NU ("#CTL#", (AND (f2, (OR (f1, (AX ("", (VAR "#CTL#"))))))))
+       NU (name, (AND (f2, (OR (f1, (AX ("", (VAR name))))))))
     | ER (f1, f2) ->
-       NU ("#CTL#", (AND (f2, (OR (f1, (EX ("", (VAR "#CTL#"))))))))
+       NU (name, (AND (f2, (OR (f1, (EX ("", (VAR name))))))))
     | AB (f1, f2) ->
-       NOT (MU ("#CTL#", (OR (f2, (AND ((NOT f1), (EX ("", (VAR "#CTL#")))))))))
+       NOT (MU (name, (OR (f2, (AND ((NOT f1), (EX ("", (VAR name)))))))))
     | EB (f1, f2) ->
-       NOT (MU ("#CTL#", (OR (f2, (AND ((NOT f1), (AX ("", (VAR "#CTL#")))))))))
+       NOT (MU (name, (OR (f2, (AND ((NOT f1), (AX ("", (VAR name)))))))))
     | _ -> formula
   in
   convert_post helper formula