Four-graviton scattering in eleven-dimensional supergravity is conside
red at one loop compactified on one, two and three-dimensional tori, T
he dependence on the toroidal geometry determines the known perturbati
ve and non-perturbative terms in the corresponding processes in type I
I superstring theories in ten, nine and eight dimensions. The ultra-vi
olet divergence must be regularized so that it has a precisely determi
ned finite value that is consistent both with T-duality in nine dimens
ions and with eleven-dimensional supersymmetry. (C) 1997 Elsevier Scie
nce B.V.