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Simplicity of generic Steiner bundles

Maria Chiara Brambilla (2005)

Bollettino dell'Unione Matematica Italiana

A Steiner bundle E on P n has a linear resolution of the form 0 O - 1 s O t E 0 . In this paper we prove that a generic Steiner bundle E is simple if and only if χ End E is less or equal to 1. In particular we show that either E is exceptional or it satisfies the inequality t n + 1 + n + 1 2 - 4 2 s .

Slope filtration of quasi-unipotent overconvergent F -isocrystals

Nobuo Tsuzuki (1998)

Annales de l'institut Fourier

We study local properties of quasi-unipotent overconvergent F -isocrystals on a curve over a perfect field of positive characteristic p . For a φ - -module over the Robba ring , we define the slope filtration for Frobenius structures. We prove that an overconvergent F -isocrystal is quasi-unipotent if and only if it has the slope filtration for Frobenius structures locally at every point on the complement of the curve.

Currently displaying 21 – 40 of 165