Supersymmetry constraints on type IIB supergravity - art. no. 046006

Supersymmetry is used to derive conditions on higher derivative terms in th e effective action of type IIB supergravity. Using these conditions, we are able to prove earlier conjectures that certain modular invariant interacti ons of order (alpha')(3) relative to the Einstein-Hilbert term are proporti onal to eigenfunctions of the Laplace operator on the fundamental domain of SL(2,Z). We also discuss how these arguments generalize to terms of higher order in alpha', as well as to compactifications of supergravity. [S0556-2 821(99)05102-4].