Codimension one distributions and stable rank 2 reflexive sheaves on threefolds

Abstract

We show that codimension one distributions with at most isolated singularities on certain smooth projective threefolds with Picard rank one have stable tangent sheaves. The ideas in the proof of this fact are then applied to the characterization of certain irreducible components of the moduli space of stable rank 2 reflexive sheaves on P 3 , and to the construction of stable rank 2 reflexive sheaves with prescribed Chern classes on general threefolds. We also prove that if G is a subfoliation of a codimension one distribution F with isolated singularities, then Sing(G ) is a curve. As a consequence, we give a criterion to decide whether G is globally given as the intersection of F with another codimension one distribution. Turning our attention to codimension one distributions with non isolated singularities, we determine the number of connected components of the pure 1-dimensional component of the singular scheme.

On classification and moduli spaces of holomorphic distributions

“…In [6] we have proved that codimension one distribution with at most isolated singularities on certain smooth projective threefolds with Picard rank one have also stable tangent sheaves. As a consequence we provide a characterization of certain irreducible components of the moduli space of stable rank 2 reflexive sheaves on P 3 , and we are able to give the construction of stable rank 2 reflexive sheaves with prescribed Chern classes on general threefolds.…”

Codimension 1 distributions on three dimensional hypersurfaces

“…In [2,Theorem 1], the authors proved that, under the conditions above, T D is a stable rank 2 reflexive sheaf. Moreover, it was shown that there exists a non-singular, rational, irreducible component of the moduli space of stable rank 2 reflexive sheaves on P 3 whose general point corresponds to the tangent sheaf of a generic distribution.…”