English

Two Non-Vanishing results concerning the Anti-Canonical Bundle

Algebraic Geometry 2025-08-13 v3

Abstract

Let (X,Δ)(X, \Delta) be a klt threefold pair with nef anti-log canonical bundle (KX+Δ)-(K_X+\Delta). We show that κ(X,(KX+Δ))0\kappa(X, -(K_X+\Delta))\geq 0. To do so, we prove a more general equivariant non-vanishing result for anti-log canonical bundles, which is valid in any dimension.

Keywords

Cite

@article{arxiv.2305.19109,
  title  = {Two Non-Vanishing results concerning the Anti-Canonical Bundle},
  author = {Niklas Müller},
  journal= {arXiv preprint arXiv:2305.19109},
  year   = {2025}
}

Comments

v3: Slight changes in accordance with suggestions made by the referee, to appear in Nagoya Math. J. Comments are very welcome!