English

Simple obstructions and cone reduction

Algebraic Geometry 2025-05-20 v1

Abstract

Let XX be a Deligne-Mumford stack locally of finite type over an algebraically closed field kk of characteristic zero. We show that the intrinsic normal cone CXC_X of XX is supported in the subcone V(ΩX[1])\mathbb{V}(\Omega_X[-1]) (h1/h0((ΩX1))h^1/h^0((\Omega^1_X)^\vee)) of its intrinsic normal sheaf NXN_X. This leads to an alternative proof of cone reduction by cosections for CXC_X. We also discuss vanishing of simple obstructions under the Buchweitz-Flenner semiregularity map for sheaves.

Keywords

Cite

@article{arxiv.2405.16779,
  title  = {Simple obstructions and cone reduction},
  author = {F. Qu},
  journal= {arXiv preprint arXiv:2405.16779},
  year   = {2025}
}

Comments

10 pages

R2 v1 2026-06-28T16:41:13.560Z