diff --git a/pymbolic/mapper/__init__.py b/pymbolic/mapper/__init__.py
index c871e600ce83a18eee2fe481e3610356ce014b9c..26e88a4d505ed5cc164ec4dbdb9f01ed1106aa19 100644
--- a/pymbolic/mapper/__init__.py
+++ b/pymbolic/mapper/__init__.py
@@ -49,6 +49,9 @@ class Mapper(object):
     def map_lookup(self, expr, *args):
         return self.map_algebraic_leaf(expr, *args)
 
+    def map_if_positive(self, expr, *args):
+        return self.map_algebraic_leaf(expr, *args)
+
     def map_rational(self, expr, *args):
         return self.map_quotient(expr, *args)