diff --git a/examples/lean/ex4.lean b/examples/lean/ex4.lean
index 827d98c8d..72ce998b7 100644
--- a/examples/lean/ex4.lean
+++ b/examples/lean/ex4.lean
@@ -3,4 +3,4 @@ Definition a : Nat := 10
 Theorem T1 : a > 0 := Trivial
 Theorem T2 : a - 5 > 3 := Trivial
 (* The next one fails *)
-Theorem T3- : a > 11 := Trivial
\ No newline at end of file
+Theorem T3 : a > 11 := Trivial