diff --git a/dune/solvers/transferoperators/obstaclerestrictor.hh b/dune/solvers/transferoperators/obstaclerestrictor.hh
index 975850e6c66b500a492f53094e05a8c812cf15b8..7887c337743b41de95ca9ee494dfbf3e47eb62e4 100644
--- a/dune/solvers/transferoperators/obstaclerestrictor.hh
+++ b/dune/solvers/transferoperators/obstaclerestrictor.hh
@@ -26,6 +26,12 @@ public:
                           const MultigridTransfer<DiscFuncType>& transfer,
                           const Dune::BitSetVector<blocksize>& critical) = 0;
     
+    virtual void restrict(const std::vector<BoxConstraint<field_type,blocksize> >& f,
+                          std::vector<BoxConstraint<field_type,blocksize> >& t,
+                          const Dune::BitSetVector<blocksize>& fHasObstacle,
+                          const Dune::BitSetVector<blocksize>& tHasObstacle,
+                          const MultigridTransfer<DiscFuncType>& transfer,
+                          const Dune::BitSetVector<blocksize>& critical) = 0;
     
 };