Slopes of vector bundles on projective curves and applications to tight closure problems

Brenner, Holger

doi:10.1090/S0002-9947-03-03391-9

Slopes of vector bundles on projective curves and applications to tight closure problems

Author: Holger Brenner
Journal: Trans. Amer. Math. Soc. 356 (2004), 371-392
MSC (2000): Primary 13A35, 14H60
DOI: https://doi.org/10.1090/S0002-9947-03-03391-9
Published electronically: August 25, 2003
MathSciNet review: 2020037
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Abstract: We study different notions of slope of a vector bundle over a smooth projective curve with respect to ampleness and affineness in order to apply this to tight closure problems. This method gives new degree estimates from above and from below for the tight closure of a homogeneous -primary ideal in a two-dimensional normal standard-graded algebra in terms of the minimal and the maximal slope of the sheaf of relations for some ideal generators. If moreover this sheaf of relations is semistable, then both degree estimates coincide and we get a vanishing type theorem.

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