English

Non-annulation effective et positivit\'e locale des fibr\'es en droites amples adjoints

Algebraic Geometry 2007-10-15 v3

Abstract

We prove that Seshadri constants of some ample divisors are bigger than 1 on smooth threefolds whose anticanonical bundle is nef or on Fano varieties of small coindice. The main tools are (some known cases of) the Kawamata's effective non-vanishing conjecture and the adjunction theory. We prove the non-vanishing conjecture in dimension 3 in the case of line bundles of "high" volume using Kawamata's subadjunction formula.

Keywords

Cite

@article{arxiv.0707.4140,
  title  = {Non-annulation effective et positivit\'e locale des fibr\'es en droites amples adjoints},
  author = {Amaël Broustet},
  journal= {arXiv preprint arXiv:0707.4140},
  year   = {2007}
}

Comments

22 pages, in french, typos corrected

R2 v1 2026-06-21T09:02:29.597Z