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arXiv 2107.01591math.AGmath.DS
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用实莫尔斯理论证明Lefschetz定理

Lefschetz Theorem Using Real Morse Theory

Nima Rose Manjila, A. J. Parameswaran

摘要:

我们证明了莱夫谢茨超平面截口定理使用一个更简单的机器,使观察,我们可以组成莱夫谢茨超平面与一个真正的莫尔斯函数得到一个地图从品种的$\mathbb{R}$这是“接近”是一个真正的莫尔斯函数。证明使用了一种新的方法,不同于传统的使用消失圈,顶针和monodromy。利用莫尔斯理论、Lefschetz束和Bézout定理证明了平面曲线的亏格公式。然后利用形变理论的技巧证明了曲线间分歧映射的Riemann Hurwitz公式。最后,我们仅用实莫尔斯理论和正合序列证明了Lefschetz超平面截口定理.

英文摘要:

We prove the Lefschetz hyperplane section theorem using a simpler machinery by making the observation that we can compose the Lefschetz Pencil with a Real Morse function to get a map from the variety to $\mathbb{R}$ which is "close" to being a Real Morse function. The proof uses a new method unlike the conventional one which uses vanishing cycles, thimbles and monodromy. We prove the genus formula for plane curves using Morse theory, Lefschetz pencil and Bézout's theorem. And then we prove the Riemann Hurwitz formula for ramified maps between curves by employing techniques from deformation theory. Lastly, we prove the Lefschetz Hyperplane Section Theorem solely using Real Morse Theory and exact sequences.

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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