CONNECTIONS BETWEEN 11-DIMENSIONAL SUPERGRAVITY AND TYPE-II SUPERSTRINGS

The talk as presented reviewed the non-perturbative structure of certa in higher derivative terms in the type II string theory effective acti on and their connection to one-loop effects in eleven-dimensional supe rgravity compactified on a torus. This article also includes new mater ial concerning the possibility of determining ten-dimensional string a mplitudes from multi-loop effects in eleven-dimensional supergravity.