English

Effective non-vanishing conjectures for projective threefolds

Algebraic Geometry 2018-01-15 v2

Abstract

Let X be a smooth projective threefold, and let A be an ample line bundle such that KX+AK_X+A is nef. We show that if KXK_X or KX-K_X is pseudoeffective, the adjoint bundle KX+AK_X+A has global sections. We also give a very short proof of the Beltrametti-Sommese conjecture in dimension three, recently proven by Fukuma: if A is an ample line bundle such that KX+2AK_X+2A is nef, the adjoint bundle KX+2AK_X+2A has global sections.

Keywords

Cite

@article{arxiv.0811.3059,
  title  = {Effective non-vanishing conjectures for projective threefolds},
  author = {Amaël Broustet and Andreas Höring},
  journal= {arXiv preprint arXiv:0811.3059},
  year   = {2018}
}

Comments

8 pages, changed metadata

R2 v1 2026-06-21T11:43:09.830Z