Excision of singularities by stringy domain walls

We study supersymmetric domain walls on S-1/Z(2) orbifolds. The supergravit y solutions in the bulk are given by the attractor equation associated with Calabi-Yau (CY) spaces and have a naked space-time singularity at some \y( s)\. We are looking for possibilities to cut off this singularity with the second wall by a stringy mechanism. We use the collapse of the CY cycle at \y(c)\ which happens before and at a finite distance from the space-time si ngularity. In our example with three Kahler moduli the second wall is at th e end of the moduli space at \y(c)\ where also the enhancement of SU(2) gau ge symmetry takes place so that \y(e)\=\y(c)\< \y(s)\. The physics of the e xcision of a naked singularity via the enhancon in the context of domain wa ll has an interpretation on the heterotic side related to R -->1/R duality. The position of the enhancon is given by the equation R(\y(e)\)=1. (C) 200 1 American Institute of Physics.