  In the literature it is assumed that the parton to hadron fragmentation
function cannot be studied by using the lattice QCD method because of the sum
over the (unobserved) outgoing hadronic states. However, in this paper we find
that since the hadron formation from the partons can be studied by using the
lattice QCD method, the parton to hadron fragmentation function can be studied
by using the lattice QCD method by using the LSZ reduction formula for the
partonic processes.
