diff --git a/dune/porsol/blackoil/fluid/BlackoilDefs.hpp b/dune/porsol/blackoil/fluid/BlackoilDefs.hpp
index 091e92b99..e6e4afcbb 100644
--- a/dune/porsol/blackoil/fluid/BlackoilDefs.hpp
+++ b/dune/porsol/blackoil/fluid/BlackoilDefs.hpp
@@ -22,7 +22,8 @@
 
 
 #include <dune/common/fvector.hh>
-
+#include <dune/common/fmatrix.hh>
+#include <boost/static_assert.hpp>
 
 namespace Opm
 {
@@ -39,6 +40,9 @@ namespace Opm
         typedef double Scalar;
         typedef Dune::FieldVector<Scalar, numComponents> CompVec;
         typedef Dune::FieldVector<Scalar, numPhases> PhaseVec;
+        BOOST_STATIC_ASSERT(int(numComponents) == int(numPhases));
+        typedef Dune::FieldMatrix<Scalar, numComponents, numPhases> PhaseToCompMatrix;
+        typedef Dune::FieldMatrix<Scalar, numPhases, numPhases> PhaseJacobian;
     };
 
 } // namespace Opm