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arXiv 1901.09013math.AGmath.NT
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同余覆盖的基本维数

The Essential Dimension of Congruence Covers

Benson Farb, Mark Kisin, Jesse Wolfson

AI总结:

本文利用p可除群和有限平坦群概形的形变理论,计算了主极化阿贝尔簇模空间同余覆盖的基本维数,并应用于曲线模空间及局部对称簇,回答了Kronecker-Klein问题。

摘要:

考虑代数函数 $\Phi_{g,n}$,它将一个一般的 $g$ 维阿贝尔簇赋予一个 $n$ 阶挠点。Kronecker 和 Klein 首先提出的一个问题是:在有理变量替换后,函数 $\Phi_{g,n}$ 能被写成 $d$ 个变量的代数函数的最小 $d$ 是多少?利用 $p$ 可除群和有限平坦群概形的形变理论技术,我们通过计算主极化阿贝尔簇模空间的同余覆盖的基本维数和 $p$ 维数来回答这个问题。我们将此结果应用于计算亏格 $g$ 曲线模空间及其超椭圆轨迹的同余覆盖的基本 $p$ 维数,以及某些局部对称簇的基本 $p$ 维数。

英文摘要:

Consider the algebraic function $Φ_{g,n}$ that assigns to a general $g$-dimensional abelian variety an $n$-torsion point. A question first posed by Kronecker and Klein asks: What is the minimal $d$ such that, after a rational change of variables, the function $Φ_{g,n}$ can be written as an algebraic function of $d$ variables? Using techniques from the deformation theory of $p$-divisible groups and finite flat group schemes, we answer this question by computing the essential dimension and $p$-dimension of congruence covers of the moduli space of principally polarized abelian varieties. We apply this result to compute the essential $p$-dimension of congruence covers of the moduli space of genus $g$ curves, as well as its hyperelliptic locus, and of certain locally symmetric varieties.

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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