English

Some results on fake quadrics

Algebraic Geometry 2025-03-21 v9

Abstract

In this paper, we give a criterion to assess the effectiveness and ampleness of divisors on a fake quadric surface SS, and then we establish a relationship between the cones: \Eff˚(S)=\Amp(S)\SAmp(S)=\Mov(S)\Nef(S)=\Eff(S)=\Amp(S).\mathring{\Eff}(S)=\Amp(S)\subset \SAmp(S)=\Mov(S) \subset \Nef(S)=\Eff(S)=\overline{\Amp(S)}. In particular, we prove that any fake quadric of odd type does not contain a negative curve. This result is central to our manuscript. As applications, first we give that any fake quadric is a fibration over P1;\mathbb P^1; Subsequently, we show that no fake quadric can be embedded in P4\mathbb P^4; Finally, we prove that the fake quadric SS possesses the bounded cohomology property. This property is characterized by the existence of a positive constant cSc_{S} such that h1(\COS(C))cSh0(\COS(C))h^1(\CO_S(C))\leq c_S h^0(\CO_S(C)) for any curve CSC \subset S.

Cite

@article{arxiv.2307.11175,
  title  = {Some results on fake quadrics},
  author = {Jianqiang Yang},
  journal= {arXiv preprint arXiv:2307.11175},
  year   = {2025}
}

Comments

22 pages. comments are welcome

R2 v1 2026-06-28T11:36:23.484Z