论文标题
dabkowski-sahi不变式和$ 4 $ - moves链接
The Dabkowski-Sahi invariant and $4$-moves for links
论文作者
论文摘要
达布科夫斯基（Dabkowski）和萨希（Sahi）定义了$ 3 $ -sphere中的链接的不变性，该链接保留在$ 4 $ -Moves以下。这个不变是该链接补充的基本组的商。通常很难区分给定链接的dabkowski-sahi不变性。在本文中，我们为链接的dabkowski-sahi不变性与相应的琐碎链接的同构存在提供了必要条件。使用这种条件，我们为链接提供了实用的障碍，使其琐碎的链接最高为$ 4 $。
Dabkowski and Sahi defined an invariant of a link in the $3$-sphere, which is preserved under $4$-moves. This invariant is a quotient of the fundamental group of the complement of the link. It is generally difficult to distinguish the Dabkowski-Sahi invariants of given links. In this paper, we give a necessary condition for the existence of an isomorphism between the Dabkowski-Sahi invariant of a link and that of the corresponding trivial link. Using this condition, we provide a practical obstruction to a link to be trivial up to $4$-moves.
