diff --git a/src/kernel/formatter.cpp b/src/kernel/formatter.cpp
index 3c6d60f352..c705e8eb93 100644
--- a/src/kernel/formatter.cpp
+++ b/src/kernel/formatter.cpp
@@ -164,7 +164,10 @@ struct print_expr_fn {
             bool first = true;
             for (auto l : ls) {
                 if (first) first = false; else out() << " ";
-                out() << l;
+                if (is_max(l) || is_imax(l))
+                    out() << "(" << l << ")";
+                else
+                    out() << l;
             }
             out() << "}";
         }