paper

Consistency Conditions for Branes at Orbifold Singularities

arXiv:hep-th/9705030 · doi:10.1016/S0550-3213(97)00450-1

Abstract

We discuss consistency conditions for branes at orbifold singularities. The conditions have a world-sheet interpretation in terms of tadpole cancellation and a space-time interpretation in terms of anomalies. As examples, we consider type II and type I branes on $C^{2} / Z_{M}$ orbifolds. We give orientifold constructions of phases of type I or heterotic string theory, involving branches with extra tensor multiplets, which arise when small SO(32) instantons sit on orbifold singularities.

harvmac, 14 pages, added references