Divisibility of Frobenius eigenvalues on l-adic cohomology

被引:0
|
作者
Esnault, Helene [1 ]
Wan, Daqing [2 ]
机构
[1] Free Univ Berlin, Arnimallee 3, D-14195 Berlin, Germany
[2] Univ Calif Irvine, Dept Math, Irvine, CA 92697 USA
关键词
Ax-Katz theorem; cohomological divisibility; Hodge level; HODGE TYPE;
D O I
10.1007/s12044-022-00697-0
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
For a projective variety defined over a finite field with q elements, it is shown that as algebraic integers, the eigenvalues of the geometric Frobenius acting on l-adic cohomology have higher than known q-divisibility beyond the middle dimension. This sharpens both Deligne's integrality theorem [2, Corollary 5.5.3] and the cohomological divisibility theorem [10, Theorem 4.1]. A similar lower bound is proved for the Hodge level for a complex projective variety beyond the middle dimension, improving earlier results in this direction. The affine version of our results for the compactly supported cohomology is still open in general.
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页数:7
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