  In J. Stat. Phys. 115, 415-449 (2004) Brydges, Guadagni and Mitter proved the
existence of multiscale expansions of a class of lattice Green's functions as
sums of positive definite finite range functions (called fluctuation
covariances). The lattice Green's functions in the class considered are
integral kernels of inverses of second order positive self adjoint operators
with constant coefficients and fractional powers thereof. The fluctuation
coefficients satisfy uniform bounds and the sequence converges in appropriate
norms to a smooth, positive definite, finite range continuum function. In this
note we prove that the convergence is actually exponentially fast.
