English

Canonical blow-ups of Grassmann manifolds

Algebraic Geometry 2021-08-26 v2 Complex Variables Differential Geometry

Abstract

We introduce certain canonical blow-ups Ts,p,n\mathcal T_{s,p,n}, as well as their distinct submanifolds Ms,p,n\mathcal M_{s,p,n}, of Grassmann manifolds G(p,n)G(p,n) by partitioning the Pl\"ucker coordinates with respect to a parameter ss. Various geometric aspects of Ts,p,n\mathcal T_{s,p,n} and Ms,p,n\mathcal M_{s,p,n} are studied, for instance, the smoothness, the holomorphic symmetries, the (semi-)positivity of the anti-canonical bundles, the existence of K\"ahler-Einstein metrics, the functoriality, etc. In particular, we introduce the notion of homeward compactification, of which Ts,p,n\mathcal T_{s,p,n} are examples, as a generalization of the wonderful compactification. Lastly, a generalization of Ts,p,n\mathcal T_{s,p,n} according to vector-valued parameters s\overline s is given, and open questions are raised.

Keywords

Cite

@article{arxiv.2007.06200,
  title  = {Canonical blow-ups of Grassmann manifolds},
  author = {Hanlong Fang},
  journal= {arXiv preprint arXiv:2007.06200},
  year   = {2021}
}

Comments

With an appendix by Kexing Chen. Typos corrected and references updated. Comments are welcome