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arXiv 0907.1718math.GT
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曲面的Abel覆盖与水平L映射类群的同调

Abelian covers of surfaces and the homology of the level L mapping class group

Andrew Putman

摘要:

计算了曲面的泛交换$\Z / L \Z$ -覆盖的第一有理同调群中系数的映射类群的第一同调群。如果曲面有一个标记点,则答案是$\Q^{τ(L)}$,其中$τ(L)$是$L$的正因子数。如果曲面只有一个边界分量,则答案为$\Q$。我们还对映射类群的级别$L$子群执行相同的计算。设置$H_L = H_1(Σ_g;\Z/L\Z)$。如果曲面有一个标记点,则答案是$\Q[H_L]$,即$H_L$的有理群环。如果曲面只有一个边界分量,则答案为$\Q$。

英文摘要:

We calculate the first homology group of the mapping class group with coefficients in the first rational homology group of the universal abelian $\Z / L \Z$-cover of the surface. If the surface has one marked point, then the answer is $\Q^{τ(L)}$, where $τ(L)$ is the number of positive divisors of $L$. If the surface instead has one boundary component, then the answer is $\Q$. We also perform the same calculation for the level $L$ subgroup of the mapping class group. Set $H_L = H_1(Σ_g;\Z/L\Z)$. If the surface has one marked point, then the answer is $\Q[H_L]$, the rational group ring of $H_L$. If the surface instead has one boundary component, then the answer is $\Q$.

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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