We construct a moduli space of stable pairs over a smooth projective variety,
parametrizing morphisms from a fixed coherent sheaf to a varying sheaf of fixed
topological type, subject to a stability condition. This generalizes the notion used by
Pandharipande and Thomas, following Le Potier, where the fixed sheaf is the
structure sheaf of the variety. We then describe the relevant deformation and
obstruction theories. We also show the existence of the virtual fundamental class in
special cases.
Keywords
moduli space, stable pair, deformation, obstruction,
virtual fundamental class