impressive accuracy of the numerical results this new approach displays also the typical universal character of a RG formulation, in that it is applicable with some particular changes for a variety of problems and was named the Density Matrix RG (DMRG) .\
The dramatic success of the DMRG method has changed the picture of real-space RG techniques completely and has been applied until now in very different fields of scientific research . The method itself is a rather complicated algorithm and a detailed description together with some examples is given by S.R. White [@wh93].\
Despite of all the excitement concerning DMRG, the method has some important restrictions which are given by the method itself and therefore cannot be removed by applying simple changes to the DMRG algorithm. Here we mention the three main restrictions briefly:

1.  The chief limitation of DMRG is dimensionality. Although higher dimensional variations are not forbidden in general, it becomes a complicated task. Recent applications of DMRG to finite width strips in two dimensions show a declining accuracy with the width. Therefore a successful approach for two dimensions in general or even higher dimension has never been worked out.

2.  DMRG is by definition an algorithm 