摘要翻译：
本文计算了具有两个未指定三分枝点的铅笔的M_g曲线的轨迹类。这是M_g上的几何除数的第一个例子，它不是拟稳定曲线模空间上的除数的回拉。在M_g的最小模型程序中，椭圆尾被尖点代替的空间是第一次除数压缩的结果。特别地，我们证明了当限制在椭圆尾的边界因子时，我们的因子可以拾取Fermat三次尾的轨迹。对于具有特殊分枝性质的一般曲线的覆盖，我们也给出了各种枚举应用。
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英文标题：
《The Fermat cubic and special Hurwitz loci in M_g》
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作者：
Gavril Farkas
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最新提交年份：
2008
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分类信息：

一级分类：Mathematics        数学
二级分类：Algebraic Geometry        代数几何
分类描述：Algebraic varieties, stacks, sheaves, schemes, moduli spaces, complex geometry, quantum cohomology
代数簇，叠，束，格式，模空间，复几何，量子上同调
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英文摘要：
  We compute the class of the locus in M_g of curves having a pencil with two unspecified triple ramification points. This is the first example of a geometric divisor on M_g which is not the pull-back of a divisor on the moduli space of pseudo-stable curves. This space, in which elliptic tails are replaced by cusps, appears as a result of the first divisorial contraction in the minimal model program for M_g. In particular, we show that our divisor picks-up the locus of Fermat cubic tails when restricted to the boundary divisor of elliptic tails. We also give various enumerative applications concerning coverings of the generic curve having special ramification behaviour.
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PDF链接：
https://arxiv.org/pdf/0711.1327