  We derive low-temperature properties of the large-U Hubbard model in two and
three dimensions from exact series-expansion results for high temperatures.
Convergence problems and limited available information prevent a direct or
Pade'-type extrapolation. We propose a new method of extrapolation, which is
restricted to large U and low hole densities, for which the problem can be
mapped on that of a system of weakly interacting holes. In the new formulation
an extrapolation down to T=0 can be obtained, but it can be trusted for the
presently available series data for kT/t < 0.05 and for hole densities below
0.2 only. Implications for the magnetic phase diagram are discussed.
