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arXiv 2008.04138math.GT
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签名双片亏格的一个下界

A lower bound for the doubly slice genus from signatures

Patrick Orson, Mark Powell

摘要:

3-球面中纽结的双切片亏格是4-球面中纽结以横截面形式出现的无纽结可定向曲面中的最小亏格。利用纽结的经典签名函数给出了双片亏格的一个新的下界。我们结合这与一个上界,由于C。McDonald证明了对每一个非负整数$N$,存在一个纽结,其中切片亏格与双切片亏格之差正好是$N$,改进了W.他说这个差别可以是任意大的。

英文摘要:

The doubly slice genus of a knot in the 3-sphere is the minimal genus among unknotted orientable surfaces in the 4-sphere for which the knot arises as a cross-section. We use the classical signature function of the knot to give a new lower bound for the doubly slice genus. We combine this with an upper bound due to C. McDonald to prove that for every nonnegative integer $N$ there is a knot where the difference between the slice and doubly slice genus is exactly $N$, refining a result of W. Chen which says this difference can be arbitrarily large.

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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