English

Singular contact varieties

Algebraic Geometry 2024-04-15 v2

Abstract

In this note we propose the generalization of the notion of a holomorphic contact structure on a manifold (smooth variety) to varieties with rational singularities and prove basic properties of such objects. Natural examples of singular contact varieties come from the theory of nilpotent orbits: every projectivization of the closure of a nilpotent orbit in a semisimple Lie algebra satisfies our definition after normalization. We show the correspondence between symplectic varieties with the structure of a C\mathbb{C}^*-bundle and the contact ones along with the existence of the stratification \`a la Kaledin. In the projective case we demonstrate the equivalence between crepant and contact resolutions of singularities, show the uniruledness and give a full classification of projective contact varieties in dimension 3.

Keywords

Cite

@article{arxiv.2212.07930,
  title  = {Singular contact varieties},
  author = {Robert Śmiech},
  journal= {arXiv preprint arXiv:2212.07930},
  year   = {2024}
}

Comments

Accepted for publication in manuscripta mathematica. 29 pages, 2nd version containing substantial changes in the presentation of the results and some new ones. In particular, there is now a classification result in dimension 3 and a non-example that satisfies the weaker definition of Campana-Flenner (with nonrational singularities)

R2 v1 2026-06-28T07:36:55.102Z