Ginsparg-Wilson Relation and Lattice Supersymmetry
  The Ginsparg-Wilson(G-W) relation is extended for supersymmetric free theories on a lattice.   Exact lattice supersymmetry(SUSY) can be defined without any ambiguities in difference operators. The lattice action constructed by a block-spin transformation is invariant under the symmetry. $U(1)_R$ symmetry on the lattice is also realized as one of exact symmetries.   For an application, the extended G-W relation is given for a two-dimensional model with chiral-multiplets. It is argued that the relation may be generalized for interacting cases. 
Hiroto So and Naoya Ukita