English

On the Picard number of almost Fano threefolds with pseudo-index >1

Algebraic Geometry 2007-05-23 v1

Abstract

We study Gorenstein almost Fano threefolds X with canonical singularities and pseudoindex > 1. We show that the maximal Picard number of X is 10 in general, 3 if X is Fano, and 8 if X is toric. Moreover, we characterize the boundary cases. In the Fano case, we prove that the generalized Mukai conjecture holds.

Keywords

Cite

@article{arxiv.math/0603090,
  title  = {On the Picard number of almost Fano threefolds with pseudo-index >1},
  author = {C. Casagrande and P. Jahnke and I. Radloff},
  journal= {arXiv preprint arXiv:math/0603090},
  year   = {2007}
}

Comments

18 pages