Exceptional collections and D-branes probing toric singularities

Abstract: We demonstrate that a strongly exceptional collection on a singular toric surface can be used to derive the gauge theory on a stack of D3-branes probing the Calabi-Yau singularity caused by the surface shrinking to zero size. A strongly exceptional collection, i.e., an ordered set of sheaves satisfying special mapping properties, gives a convenient basis of D-branes. We find such collections and analyze the gauge theories for weighted projective spaces, and many of the Y p,q and Lp,q,r spaces. In particular, we prove the strong exceptionality for all p in the Y p,p−1 case, and similarly for the Y p,p−2r case.