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2606.20473 2026-06-19 math.GN 新提交

Invariants of the Colored Braid Groupoid

彩色辫子群胚的不变量

Illia E. Rohozhkin

AI总结 将辫子视为平面点的动力系统,通过Delaunay三角剖分定义抽象群胚,构造彩色辫子群胚的表示并计算不变量。

Comments 30 pages, 13 figures

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AI中文摘要

本文将辫子视为平面点的动力系统。该动力系统的状态由Delaunay三角剖分给出。这一构造使得定义抽象群胚$\overset{abc}{\mathcal{G}^{4}_{n+3}}$成为可能,该群胚给出了彩色辫子群胚$\text{ColB}(n)$的一个表示。我们定义了同态${f}_{n+3}:\overset{abc}{\mathcal{G}^{4}_{n+3}} \rightarrow\text{GL}_{2n+1}(\mathbb{Q})$和${f}'_{n+3}:\overset{abc}{\mathcal{G}^{4}_{n+3}} \rightarrow\text{GL}_{2n+1}(\mathbb{C})$,并描述了计算所得不变量的一种算法。

英文摘要

In this paper, a braid is regarded as a dynamical system of points in the plane. The states of this dynamical system are given by Delaunay triangulations. This construction makes it possible to define an abstract groupoid $\overset{abc}{\mathcal{G}^{4}_{n+3}}$, which gives a representation of the colored braid groupoid $\text{ColB}(n)$. We define homomorphisms ${f}_{n+3}:\overset{abc}{\mathcal{G}^{4}_{n+3}} \rightarrow\text{GL}_{2n+1}(\mathbb{Q})$ and ${f}'_{n+3}:\overset{abc}{\mathcal{G}^{4}_{n+3}} \rightarrow\text{GL}_{2n+1}(\mathbb{C})$, and describe an algorithm for computing the resulting invariants.

2606.14435 2026-06-19 math.DS math.GN 交叉投稿

Shadowing in Dynamical Systems: Zero-dimensional Extensions and Inverse Limits

动力系统中的跟踪性:零维扩张与逆极限

Dekui Peng

AI总结 本文证明每个紧致豪斯多夫动力系统都是有限型转移的逆极限的因子,并识别了度量情形下跟踪性提供的额外稳定性,即具有跟踪性的紧致度量系统是满射粘合映射的有限型转移逆极限的因子。

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AI中文摘要

Good和Meddaugh证明了每个具有跟踪性的紧致度量动力系统都是有限型转移的逆序列的逆极限的因子。我们首先证明,仅就这一因子表示而言,这两个假设都是不必要的:每个紧致豪斯多夫动力系统都是有限型转移的逆系统的逆极限的因子。特别地,这种符号逆极限表示的存在性并非跟踪性所特有。本文的主要贡献在于识别了度量情形下跟踪性所提供的额外稳定性。我们证明每个具有跟踪性的紧致度量系统都是粘合映射为满射的有限型转移逆序列的逆极限的因子。因此,该逆序列满足Mittag-Leffler条件,并且相应的零维扩张仍具有跟踪性。这加强了Good和Meddaugh的度量表示定理,并完成了他们关于有限型转移的Mittag-Leffler逆序列的ALP因子的刻画。最后,对于任意紧致豪斯多夫空间,我们证明每个紧致跟踪系统共轭于具有因子粘合映射的可度量跟踪系统的逆极限。在此意义上,紧致跟踪系统是由有限型转移通过最多三次应用两个保持跟踪性的操作(取Mittag-Leffler逆极限和过渡到ALP因子)生成的。

英文摘要

Good and Meddaugh proved that every compact metric dynamical system with shadowing is a factor of the inverse limit of an inverse sequence of shifts of finite type. We show first that, for this factor representation alone, both assumptions are unnecessary: every compact Hausdorff dynamical system is a factor of the inverse limit of an inverse system of shifts of finite type. In particular, the mere existence of such a symbolic inverse-limit representation is not specific to shadowing. The main contribution of the paper is to identify the additional stability which shadowing provides in the metric case. We prove that every compact metric system with shadowing is a factor of the inverse limit of an inverse sequence of shifts of finite type whose bonding maps are surjective. Hence the inverse sequence satisfies the Mittag-Leffler condition, and the corresponding zero-dimensional extension still has shadowing. This strengthens the metric representation theorem of Good and Meddaugh and completes their characterization in terms of ALP factors of Mittag-Leffler inverse sequences of shifts of finite type. Finally, for arbitrary compact Hausdorff spaces, we show that every compact shadowing system is conjugate to the inverse limit of metrizable shadowing systems with factor bonding maps. In this sense, compact shadowing systems are generated from shifts of finite type by applying, at most three times, the two shadowing-preserving operations of taking Mittag-Leffler inverse limits and passing to ALP factors.

2307.15130 2026-06-19 cs.CG math.GN 版本更新

Bounding the Interleaving Distance for Mapper Graphs with a Loss Function

Erin W. Chambers, Elizabeth Munch, Sarah Percival, Bei Wang

Comments Updating to fix some typos

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英文摘要

Data consisting of a graph with a function mapping into $\mathbb{R}^d$ arise in many data applications, encompassing structures such as Reeb graphs, geometric graphs, and knot embeddings. As such, the ability to compare and cluster such objects is required in a data analysis pipeline, leading to a need for distances between them. In this work, we study the interleaving distance on discretization of these objects, called mapper graphs when $d=1$, where functor representations of the data can be compared by finding pairs of natural transformations between them. However, in many cases, computation of the interleaving distance is NP-hard. For this reason, we take inspiration from recent work by Robinson to find quality measures for families of maps that do not rise to the level of a natural transformation, called assignments. We then endow the functor images with the extra structure of a metric space and define a loss function which measures how far an assignment is from making the required diagrams of an interleaving commute. Finally we show that the computation of the loss function is polynomial with a given assignment. We believe this idea is both powerful and translatable, with the potential to provide approximations and bounds on interleavings in a broad array of contexts.