diff --git a/src/lib/CoAlgFormula.ml b/src/lib/CoAlgFormula.ml
index d38cf08c9c9156b84764e91678f2570df2e6bb39..ef5f85b0c8a4012fc3017ca46b5eb9484fb924f3 100644
--- a/src/lib/CoAlgFormula.ml
+++ b/src/lib/CoAlgFormula.ml
@@ -819,12 +819,16 @@ and parse_rest symtab ts =
       FUS (false, f)
   | A.Kwd "μ" ->
       let (_, _, s) = boxinternals true "." in
-      let f1 = parse_rest symtab ts in
-      MU (s, f1)
+	  let symbol = Stream.next gensym in
+	  let newtab = (s, symbol) :: symtab in
+      let f1 = parse_rest newtab ts in
+      MU (symbol, f1)
   | A.Kwd "ν" ->
       let (_, _, s) = boxinternals true "." in
-      let f1 = parse_rest symtab ts in
-      NU (s, f1)
+	  let symbol = Stream.next gensym in
+	  let newtab = (s, symbol) :: symtab in
+      let f1 = parse_rest newtab ts in
+      NU (symbol, f1)
   | A.Kwd "AF" ->
 	  let f = parse_rest symtab ts in
 	  AF f