English

On the jumping phenomenon of $\dim_{\mathbb{C}}H^q(\mathcal{X}_t,\mathcal{E}_t)$

Differential Geometry 2020-01-10 v3 Algebraic Geometry Complex Variables

Abstract

Let XX be a compact complex manifold and EE be a holomorphic vector bundle on XX. Given a deformation (X,E)(\mathcal{X},\mathcal{E}) of the pair (X,E)(X,E) over a small polydisk BB centered at the origin, we study the jumping phenomenon of the cohomology groups dimCHq(Xt,Et)\dim_{\mathbb{C}}H^q(\mathcal{X}_t,\mathcal{E}_t) near t=0t = 0. Generalizing previous results of X. Ye for the tangent bundle E=TXtE = T_{\mathcal{X}_t} and exterior powers of the cotangent bundle E=ΩXtpE = \Omega^p_{\mathcal{X}_t}, we show that there are precisely two cohomological obstructions to the stability of dimCHq(Xt,Et)\dim_{\mathbb{C}}H^q(\mathcal{X}_t,\mathcal{E}_t), which can be expressed explicitly in terms of the Maurer-Cartan element associated to the deformation (X,E)(\mathcal{X},\mathcal{E}). As an application, we study the jumping phenomenon of the dimension of the cohomology group H1(Xt,End(TXt))H^1(\mathcal{X}_t,\text{End}(T_{\mathcal{X}_t})) which is related to a question raised by physicists.

Keywords

Cite

@article{arxiv.1601.06472,
  title  = {On the jumping phenomenon of $\dim_{\mathbb{C}}H^q(\mathcal{X}_t,\mathcal{E}_t)$},
  author = {Kwokwai Chan and Yat-Hin Suen},
  journal= {arXiv preprint arXiv:1601.06472},
  year   = {2020}
}

Comments

21 pages; v3: minor modifications, to appear in Asian J. Math