  The transport coefficients for a gas of smooth, inelastic hard spheres are
obtained from the Boltzmann equation in the form of Green-Kubo relations. The
associated time correlation functions are not simply those constructed from the
fluxes of conserved densities. Instead, fluxes constructed from the reference
local homogeneous distribution occur as well. The analysis exposes potential
problems associated with a straightforward extension of linear response methods
to granular systems.
