Fano manifolds with long extremal rays

Marco Andreatta; Gianluca Occhetta

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Fano manifolds with long extremal rays

Marco Andreatta·Gianluca Occhetta

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Abstract

Let X be a Fano manifold of pseudoindex i_X whose Picard number is at least two and let R be an extremal ray of X with exceptional locus Exc(R). We prove an inequality which bounds the length of R in terms of i_X and of the dimension of Exc(R) and we investigate the border cases. In particular we classify Fano manifolds X of pseudoindex i_X obtained blowing up a smooth variety Y along a smooth subvariety T such that dim T < i_X.

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BibTeX RIS

Marco Andreatta, Gianluca Occhetta. 2005-04-13. Fano manifolds with long extremal rays. https://arxiv.org/abs/math/0504265

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