arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.00298math.GT
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纽结投影的子弦图

Sub-chord diagrams of knot projections

Noboru Ito, Yusuke Takimura

摘要:

弦图是具有成对点的圆,每对点由弦连接。每个通用沉浸球面曲线通过将每个弦与二重点的两个原像关联来提供弦图。任何两条球面曲线都可以通过三种类型的局部替换RI、RII和RIII的有限序列相关联,称为Reidemeister移动。本研究通过应用由与局部替换相关的分支的连接定义的移动RI、强RII、弱RII、强RIII和弱RIII中的一个来计算嵌入任何球面曲线的全弦图中的子弦图的数量的差异(定理1)。这产生了一个新的在RI和强RIII下的整数值不变量,它提供了一个完整的分类,至少有七个二重点的素数约化球面曲线(定理2,图24):以前没有这样的不变量。该不变量表示球面曲线可以通过RI和强RIII移动的有限序列与简单闭曲线相关联的充要条件(定理3)。此外,通过计算子弦图,给出了蝇型下球面曲线的不变量(定理4)。

英文摘要:

A chord diagram is a circle with paired points with each pair of points connected by a chord. Every generic immersed spherical curve provides a chord diagram by associating each chord with two preimages of a double point. Any two spherical curves can be related by a finite sequence of three types of local replacement RI, RII, and RIII, called Reidemeister moves. This study counts the difference in the numbers of sub-chord diagrams embedded in a full chord diagram of any spherical curve by applying one of the moves RI, strong RII, weak RII, strong RIII, and weak RIII defined by connections of branches related to the local replacements (Theorem 1). This yields a new integer-valued invariant under RI and strong RIII that provides a complete classification of prime reduced spherical curves with up to at least seven double points (Theorem 2, Fig. 24): there has been no such invariant before. The invariant expresses the necessary and sufficient condition that spherical curves can be related to a simple closed curve by a finite sequence of RI and strong RIII moves (Theorem 3). Moreover, invariants of spherical curves under flypes are provided by counting sub-chord diagrams (Theorem 4).

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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