论文标题

对数双分支周期

Logarithmic double ramification cycles

论文作者

Holmes, D., Molcho, S., Pandharipande, R., Pixton, A., Schmitt, J.

论文摘要

令$ a =(a_1,\ ldots,a_n)$是整数的向量,总计为$ k(2g-2+n)$。在曲线的模态上,双重分支周期$ \ Mathsf {dr} _ {g,a} \ in \ Mathsf {ch}^g(\ Mathcal {M Mathcal {M} _ {g,n})$在曲线的Moduli空间上是Abel-Jacobi locus of Abel-Jacobi locus of abel-jacobi locus ob abel-jacobi locus curves $( $$ \ MATHCAL {o} _C \ big(\ sum_ {\ sum_ {i = 1}^n a_i x_i \ big)\,\ simeq \,\ big(ω^{\ mathsf {logSf {log}} _ {c} _ {c} $ \ MATHCAL {M} _ {G,N} $解决Abel-Jacobi Map的不确定。福尔摩斯已经表明,$ \ mathsf {dr} _ {g,a} $承认一个规范的升降机$ \ mathsf {logdr} _ {g,a} \ in \ mathsf {logCh}^g(\ nogch}^g(\ nogCal {\ mathcal {m} _ {m} _ {g,n} _ {g,n})爆破。 本文的主要结果是$ \ mathsf {logdr} _ {g,a} $的显式公式,该公式将Pixton的公式用于$ \ Mathsf {dr} _ {g,a} $。核心思想是在曲线的模量空间(遵循Caporaso,Kass-Pagani和Abreu-Pacini)上研究普遍的Jacobian,以了解某些稳定条件。使用Holmes-Schwarz的标准,Bae-Holmes-Pandharipande-Schmitt-Schwarz的通用双分支理论应用于通用线束,决定了对数双重冲突循环。以分段多项式语言编写的结果公式取决于稳定性条件(并接受了一项隔离式研究)。计算了几个对数和较高双重分支周期的例子。

Let $A=(a_1,\ldots, a_n)$ be a vector of integers which sum to $k(2g-2+n)$. The double ramification cycle $\mathsf{DR}_{g,A}\in \mathsf{CH}^g(\mathcal{M}_{g,n})$ on the moduli space of curves is the virtual class of an Abel-Jacobi locus of pointed curves $(C,x_1,\ldots,x_n)$ satisfying $$\mathcal{O}_C\Big(\sum_{i=1}^n a_i x_i\Big) \, \simeq\, \big(ω^{\mathsf{log}}_{C}\big)^k\, .$$ The Abel-Jacobi construction requires log blow-ups of $\mathcal{M}_{g,n}$ to resolve the indeterminacies of the Abel-Jacobi map. Holmes has shown that $\mathsf{DR}_{g,A}$ admits a canonical lift $\mathsf{logDR}_{g,A} \in \mathsf{logCH}^g(\mathcal{M}_{g,n})$ to the logarithmic Chow ring, which is the limit of the intersection theories of all such blow-ups. The main result of the paper is an explicit formula for $\mathsf{logDR}_{g,A}$ which lifts Pixton's formula for $\mathsf{DR}_{g,A}$. The central idea is to study the universal Jacobian over the moduli space of curves (following Caporaso, Kass-Pagani, and Abreu-Pacini) for certain stability conditions. Using the criterion of Holmes-Schwarz, the universal double ramification theory of Bae-Holmes-Pandharipande-Schmitt-Schwarz applied to the universal line bundle determines the logarithmic double ramification cycle. The resulting formula, written in the language of piecewise polynomials, depends upon the stability condition (and admits a wall-crossing study). Several examples of logarithmic and higher double ramification cycles are computed.

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