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arXiv 1705.04470math.GTmath.GR
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纽结群中被Dehn填充平凡化的非平凡元

Nontrivial elements in a knot group which are trivialized by Dehn fillings

Tetsuya Ito, Kimihiko Motegi, Masakazu Teragaito

摘要:

设K是三维球面中的一个非平凡纽结,其外点为E(K),u是E(K)的基本群G(K)中的一个斜率元,由E(K)边界上的一条本质简单闭曲线表示.由于u在G(K)中的正规闭包与u的逆闭包重合,并且u及其逆u对应于斜率r、有理数或1/0,我们写作&lt;< r >&gt; = &lt;< u >&gt;。正规闭包&lt;< u >&gt;描述了E(K)的r-Dehn填充平凡化的元素。本文证明了&lt;< r_1 >&gt; =&lt;< r_2 >&gt;当且仅当r_1 = r_2,且对给定的有限斜率族S = {r_1,.,r_n},&lt;< r_1 >&gt;,&lt;< r_2>&gt;,.,且&lt;< r_n >&gt;包含无穷多个元素,除了当K是(p,q)-环面纽结且pq属于S时。我们还研究了边坡单元的正常闭包之间的包含关系。

英文摘要:

Let K be a nontrivial knot in the 3-sphere with the exterior E(K), and u in G(K), the fundamental group of E(K), a slope element represented by an essential simple closed curve on the boundary of E(K). Since the normal closure of u in G(K) coincides with that of the inverse of u, and u and its inverse u correspond to a slope r, a rational number or 1/0, we write << r >> = << u >>. The normal closure << u >> describes elements which are trivialized by r-Dehn filling of E(K). In this article, we prove that << r_1 >> =<< r_2 >> if and only if r_1 = r_2, and for a given finite family of slopes S = {r_1, ..., r_n}, the intersection of << r_1 >> , << r_2>>, ..., and << r_n >> contains infinitely many elements except when K is a (p, q)-torus knot and pq belongs to S. We also investigate inclusion relation among normal closures of slope elements.

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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