论文标题

框架链接和丝带伴生不变的基本堆

Fundamental Heap for Framed Links and Ribbon Cocycle Invariants

论文作者

Saito, Masahico, Zappala, Emanuele

论文摘要

堆是一个具有特定三元操作的集合,该组合是自我分配(TSD)的,并由具有$(x,y,z)的组示例,例如(x,y,z)\ mapsto xy xy^{ - 1} z $。我们使用堆介绍并调查了框架链接不变性。与结组类似,我们使用小组演示来定义框架链接的基本堆。基本堆是针对某些链接(例如某些圆环和椒盐脆饼链接的家庭)确定的。我们表明,对于这些链接家庭,存在从基本堆到Vinberg和Coxeter组的表达,这意味着相应的群体是无限的。还描述了与电线呈现的关系。 Cocycle不变性是使用三元自分配(TSD)共同体来定义的,该共同体是通过使用三元堆$ 2 $ cocycles作为权重的状态总和来定义的。这个不变的对应于通过堆倍增加一倍的架子的架子循环不变,而颜色可以看作是基本堆中的堆形态。为了构建不变的,开发了堆共同体的第一个计算方法。结果表明,共同体分为两种类型,称为退化和非分类,而退化部分是一维的。子复合物是基于组镶嵌物构建的,该集合允许计算非排效部分。使用构造的共生进行了共生不变性的计算,相反,证明不变值可用于得出共同体的代数特性。

A heap is a set with a certain ternary operation that is self-distributive (TSD) and exemplified by a group with the operation $(x,y,z)\mapsto xy^{-1}z$. We introduce and investigate framed link invariants using heaps. In analogy with the knot group, we define the fundamental heap of framed links using group presentations. The fundamental heap is determined for some classes of links such as certain families of torus and pretzel links. We show that for these families of links there exist epimorphisms from fundamental heaps to Vinberg and Coxeter groups, implying that corresponding groups are infinite. A relation to the Wirtinger presentation is also described. The cocycle invariant is defined using ternary self-distributive (TSD) cohomology, by means of a state sum that uses ternary heap $2$-cocycles as weights. This invariant corresponds to a rack cocycle invariant for the rack constructed by doubling of a heap, while colorings can be regarded as heap morphisms from the fundamental heap. For the construction of the invariant, first computational methods for the heap cohomology are developed. It is shown that the cohomology splits into two types, called degenerate and nondegenerate, and that the degenerate part is one dimensional. Subcomplexes are constructed based on group cosets, that allow computations of the nondegenerate part. Computations of the cocycle invariants are presented using the cocycles constructed, and conversely, it is proved that the invariant values can be used to derive algebraic properties of the cohomology.

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