diff --git a/src/lib/CoAlgFormula.ml b/src/lib/CoAlgFormula.ml
index 1a6997fbc0e9804cea2b8e8c1812283f28a34eea..4140781a54a89edbf5c4599b987ae04cedc5056d 100644
--- a/src/lib/CoAlgFormula.ml
+++ b/src/lib/CoAlgFormula.ml
@@ -262,9 +262,9 @@ let convertToMu formula =
     | ER (f1, f2) ->
        NU ("#ER#", (AND (f2, (OR (f1, (EX ("", (VAR "#ER#"))))))))
     | AB (f1, f2) ->
-       NOT (MU ("#AB#", (OR (f2, (AND ((NOT f1), (AX ("", (VAR "#AU#")))))))))
+       NOT (MU ("#AB#", (OR (f2, (AND ((NOT f1), (AX ("", (VAR "#AB#")))))))))
     | EB (f1, f2) ->
-       NOT (MU ("#EB#", (OR (f2, (AND ((NOT f1), (EX ("", (VAR "#EU#")))))))))
+       NOT (MU ("#EB#", (OR (f2, (AND ((NOT f1), (EX ("", (VAR "#EB#")))))))))
     | _ -> formula
   in
   convert_post helper formula