Topology and arithmetic of resultants, II: the resultant $=1$ hypersurface (with an appendix by C. Cazanave)
Topology and arithmetic of resultants, II: the resultant $=1$ hypersurface (with an appendix by C. Cazanave)
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结果的拓扑和算术,II:结果 $=1$ 超曲面(附录由 C. Cazanave 编写)
DOI:
10.14231/ag-2017-019
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发表时间:
2015
期刊:
影响因子:
--
通讯作者:
J. Wolfson
中科院分区:
文献类型:
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作者:
B. Farb;J. Wolfson
We consider the moduli space $\mathcal{R}_n$ of pairs of monic, degree $n$ polynomials whose resultant equals $1$. We relate the topology of these algebraic varieties to their geometry and arithmetic. In particular, we compute their \'{e}tale cohomology, the associated eigenvalues of Frobenius, and the cardinality of their set of $\mathbb{F}_q$-points. When $q$ and $n$ are coprime, we show that the \'etale cohomology of $\mathcal{R}_{n/\bar{\mathbb{F}}_q}$ is pure, and of Tate type if and only if $q\equiv 1$ mod $n$. We also deduce the values of these invariants for the finite field counterparts of the moduli spaces $\mathcal{M}_n$ of $SU(2)$ monopoles of charge $n$ in $\mathbb{R}^3$, and the associated moduli space $X_n$ of strongly centered monopoles.
An appendix by Cazanave gives an alternative and elementary computation of the point counts.
DOI:
10.1515/9781400859306
发表时间:
1988
期刊:
--
影响因子:
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作者:
M. Atiyah;N. Hitchin
通讯作者:
M. Atiyah;N. Hitchin