The moduli of rank 2 reflexive sheaves on smooth 3-folds -- Peter Vermeire

We compute the expected dimension of the moduli space of torsion-free rank 2 sheaves at a point corresponding to a stable reflexive sheaf on a class of smooth projective threefolds; this class includes Fano and Calabi-Yau threefolds. Further, we show there are only two types of complete intersection Fano threefolds for which this dimension could be zero, and in each case we give an example where a moduli space is actually smooth of dimension zero.