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arXiv math/0007023math.AGmath.ACmath.RA
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理想层的正性和复杂性

Positivity and complexity of ideal sheaves

Steven Dale Cutkosky, Lawrence Ein, Robert Lazarsfeld

摘要:

问题的边界的“复杂性”的多项式理想的程度,其发电机已吸引了相当大的兴趣,成为焦点的影响调查拜耳和芒福德。本文从几何的角度研究了其中的一些结果和问题。具体来说,受Paoletti工作的启发,我们引入了一个不变量s(I),它度量了理想层I的“正性”。I的生成元的度界给出了这个s-不变量的界,但是s(I)可能很小,即使它的生成元的度很大。我们证明了s(I)计算了I的大幂次的渐近Castelnuovo-Mumford正则性,并限制了其他几种复杂性度量的渐近行为。我们还表明,这个s-不变量的行为非常好的自然几何和代数运算,从而导致大大简化建设的品种不合理的渐近规律性。主要工具是相交理论和消灭定理。

英文摘要:

The problem of bounding the "complexity" of a polynomial ideal in terms of the degrees of its generators has attracted considerable interest, brought into focus by the influential survey of Bayer and Mumford. The present paper examines some of these results and questions from a geometric perspective. Specifically, motivated by work of Paoletti we introduce an invariant s(I) that measures the "positivity" of an ideal sheaf I. Degree bounds on generators of I yield bounds on this s-invariant, but s(I) may be small even when the degrees of its generators are large. We prove that s(I) computes the asymptotic Castelnuovo-Mumford regularity of large powers of I, and bounds the asymptotic behavior of several other measures of complexity. We also show that this s-invariant behaves very well with respect to natural geometric and algebraic operations, which leads to considerably simplified constructions of varieties with irrational asymptotic regularity. The main tools are intersection theory and vanishing theorems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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