  Placing a set of branes at a Calabi-Yau singularity leads to an N=1 quiver
gauge theory. We analyze F-term deformations of such gauge theories. A generic
deformation can be obtained by making the Calabi-Yau non-commutative. We
discuss non-commutative generalisations of well-known singularities such as the
Del Pezzo singularities and the conifold. We also introduce new techniques for
deriving superpotentials, based on quivers with ghosts and a notion of
generalised Seiberg duality. The curious gauge structure of quivers with ghosts
is most naturally described using the BV formalism. Finally we suggest a new
approach to Seiberg duality by adding fields and ghost-fields whose effects
cancel each other.
