Complex symplectic structures and the ∂∂ˉ\partial \bar{\partial}-lemma

In this paper we study complex symplectic manifolds, i.e., compact complex manifolds $X$ which admit a holomorphic $(2, 0)$-form $\sigma$ which is $d$-closed and non-degenerate, and in particular the Beauville-Bogomolov-Fujiki quadric $Q_\sigma$ associated to them. We will show that if X satisfies the $\partial \bar{\partial}$-lemma, then $Q_\sigma$ is smooth if and only if $h^{2,0}(X) = 1$ and is irreducible if and only if $h^{1,1}(X) > 0$.Comment: 12 page

Contact Calabi-Yau manifolds and Special Legendrian submanifolds

We consider a generalization of Calabi-Yau structures in the context of $\alpha$-Sasakian manifolds. We study deformations of a special class of Legendrian submanifolds and classify invariant contact Calabi-Yau structures on 5-dimensional nilmanifolds. Finally we generalize to codimension $r$.Comment: 16 pages, no figures. Final version to appear in "Osaka J. Math.