A renormalisation group derivation of the overlap formulation

Using this renormalisation group blocking for overlap fermions, I re-derive the Ginsparg-Wilson equations and the lattice chiral symmetry, and show that the standard Ginsparg-Wilson relation is not the most general way of expressing chiral symmetry on the lattice, nor, for overlap fermions, the most natural. I suggest how this reformulation of the Ginsparg-Wilson relation combined with the renormalisation group formulation of overlap fermions could allow the construction of a CP-invariant lattice chiral gauge theory.