English

Varieties of general type with the same Betti numbers as $\mathbb P^1\times \mathbb P^1\times\ldots\times \mathbb P^1$

Geometric Topology 2014-11-14 v1

Abstract

We study quotients Γ\Hn\Gamma\backslash \mathbb H^n of the nn-fold product of the upper half plane H\mathbb H by irreducible and torsion-free lattices Γ<PSL2(R)n\Gamma < PSL_2(\mathbb R)^n with the same Betti numbers as the nn-fold product (P1)n(\mathbb P^1)^n of projective lines. Such varieties are called fake products of projective lines or fake (P1)n(\mathbb P^1)^n. These are higher dimensional analogs of fake quadrics. In this paper we show that the number of fake (P1)n(\mathbb P^1)^n is finite (independently of nn), we give examples of fake (P1)4(\mathbb P^1)^4 and show that for n>4n>4 there are no fake (P1)n(\mathbb P^1)^n of the form Γ\Hn\Gamma\backslash \mathbb H^n with Γ\Gamma contained in the norm-1 group of a maximal order of a quaternion algebra over a real number field.

Keywords

Cite

@article{arxiv.1411.3384,
  title  = {Varieties of general type with the same Betti numbers as $\mathbb P^1\times \mathbb P^1\times\ldots\times \mathbb P^1$},
  author = {Amir Džambić},
  journal= {arXiv preprint arXiv:1411.3384},
  year   = {2014}
}

Comments

15 pages