论文标题

多元循环和热带盖

Pluricanonical cycles and tropical covers

论文作者

Cavalieri, Renzo, Markwig, Hannah, Ranganathan, Dhruv

论文摘要

我们从对数的相交理论中提取了数值不变的系统,这些系统关于多元双重化周期,并表明这些不变性表现出了许多由双Hurwitz数字所享有的属性。它们的特性包括(i)数字可以通过具有改良的平衡条件的热带曲线计数有效计算,(ii)它们是分支在拉克化载体的条目中的分段多项式,并且(iii)它们是Fock空间上操作员的矩阵元素。这些数字是从对数的双重冲突周期中提取的,这是标准双重冲击周期的提升,以爆炸曲线的模量空间。爆炸是由热带几何形状确定的。我们表明,传统的双Hurwitz数字是精制循环的交集,与曲线的热带模量空间上分段多项式功能的共同体学类别。然后,这种观点承认了自然的,具有组合动机的,概括了对多种环境的概括。新不变的热带对应结果立即导致这些数字的结构结果。

We extract a system of numerical invariants from logarithmic intersection theory on pluricanonical double ramification cycles, and show that these invariants exhibit a number of properties that are enjoyed by double Hurwitz numbers. Among their properties are (i) the numbers can be efficiently calculated by counts of tropical curves with a modified balancing condition, (ii) they are piecewise polynomial in the entries of the ramification vector, and (iii) they are matrix elements of operators on the Fock space. The numbers are extracted from the logarithmic double ramification cycle, which is a lift of the standard double ramification cycle to a blowup of the moduli space of curves. The blowup is determined by tropical geometry. We show that the traditional double Hurwitz numbers are intersections of the refined cycle with the cohomology class of a piecewise polynomial function on the tropical moduli space of curves. This perspective then admits a natural, combinatorially motivated, generalization to the pluricanonical setting. Tropical correspondence results for the new invariants lead immediately to the structural results for these numbers.

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