The holonomy of IIB supercovariant connection

We show that the holonomy of the supercovariant connection of IIB supergravity is contained in SL(32, R). We also find that the holonomy reduces to a subgroup of SL(32 - N) K((circuled plus)^N R^32-N) for IIB supergravity backgrounds with N Killing spinors. We give the necessary and sufficient conditions for a IIB background to admit N Killing spinors. A IIB supersymmetric probe configuration can involve up to 31 linearly independent planar branes and preserves one supersymmetry.