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相关论文: Topological remarks on end and edge-end spaces

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Diestel and K\"uhn proved that the topological ends of an infinite graph are precisely its undominated graph ends, yielding a canonical embedding of the space of topological ends into the space of graph ends. For edge-ends, introduced by…

组合数学 · 数学 2026-02-27 Leandro Aurichi , Paulo Magalhães Júnior , Guilherme Eduardo Pinto

We show that the topological space of any infinite graph and its ends is normal. In particular, end spaces themselves are normal.

组合数学 · 数学 2009-11-23 Philipp Sprüssel

Every end of an infinite graph $ G $ defines a tangle of infinite order in $ G $. These tangles indicate a highly cohesive substructure in the graph if and only if they are closed in some natural topology. We characterize, for every finite…

组合数学 · 数学 2025-05-16 Jay Lilian Kneip

End-spaces of infinite graphs naturally generalise the Freudenthal boundary and sit at the interface between graph theory, geometric group theory and topology. Our main result is that every end-space can topologically be represented by a…

组合数学 · 数学 2024-09-02 Jan Kurkofka , Max Pitz

In a series of three papers we develop an end space theory for digraphs. Here in the second paper we introduce the topological space $|D|$ formed by a digraph $D$ together with its ends and limit edges. We then characterise those digraphs…

组合数学 · 数学 2020-09-08 Carl Bürger , Ruben Melcher

We define a notion of (one-sided) edge shift spaces associated to ultragraphs. In the finite case our notion coincides with the edge shift space of a graph. In general, we show that our space is metrizable and has a countable basis of…

算子代数 · 数学 2017-05-19 Daniel Gonçalves , Danilo Royer

In a series of three papers we develop an end space theory for directed graphs. As for undirected graphs, the ends of a digraph are points at infinity to which its rays converge. Unlike for undirected graphs, some ends are joined by limit…

组合数学 · 数学 2020-09-08 Carl Bürger , Ruben Melcher

Let $G$ be a graph each edge $e$ of which is given a length $\ell(e)$. This naturally induces a distance $d_\ell(x,y)$ between any two vertices $x,y$, and we let $\ell-TOP$ denote the completion of the corresponding metric space. It turns…

组合数学 · 数学 2009-12-14 Agelos Georgakopoulos

In a previous joint work with Aurichi and Magalh\~aes Jr., we showed that the topological spaces arising from the edge-end structure of infinite graphs define a proper subfamily of those obtained through the well-known (vertex-)ends. This…

一般拓扑 · 数学 2025-08-26 Lucas Real

Suppose $G$ is a finitely generated infinite group, and $\mathcal G$ is a graph of groups decomposition of $G$ such that the edge groups are finite. This paper establishes that the topology of the Floyd boundary of $G$ is uniquely…

群论 · 数学 2024-01-02 Subhajit Chakraborty , Ravi Tomar

Directions of graphs were originally introduced in the study of a cops-and-robbers kind of game, while the study of end spaces has been used to generalize classical graph-theoretical results to infinite graphs, such as Halin's…

组合数学 · 数学 2025-10-21 Gustavo Boska , Matheus Duzi , Paulo Magalhães Júnior

We show that every connected graph can be approximated by a normal tree, up to some arbitrarily small error phrased in terms of neighbourhoods around its ends. The existence of such approximate normal trees has consequences of both…

组合数学 · 数学 2021-02-05 Jan Kurkofka , Ruben Melcher , Max Pitz

There are different definitions of ends in non-locally-finite graphs which are all equivalent in the locally finite case. We prove the compactness of the end-topology that is based on the principle of removing finite sets of vertices and…

组合数学 · 数学 2009-10-31 B. Krön

We propose a homology theory for locally compact spaces with ends in which the ends play a special role. The approach is motivated by results for graphs with ends, where it has been highly successful. But it was unclear how the original…

代数拓扑 · 数学 2011-05-26 Reinhard Diestel , Philipp Sprüssel

Without leaving finite mathematics and using finite topological spaces only, we give a definition of homeomorphisms of finite abstract simplicial complexes or finite graphs. Besides exploring the definition in various contexts, we add some…

组合数学 · 数学 2023-01-10 Oliver Knill

In 1992, Diestel asked which topological spaces could be represented as the end space of some graph. In 2023, Pitz provided a solution to this question by giving a topological characterization of end spaces using a hereditarily complete…

In infinite graph theory, the notion of ends, first introduced by Freudenthal and Jung for locally finite graphs, plays an important role when generalizing statements from finite graphs to infinite ones. Nash-Willian's Tree-Packing Theorem…

组合数学 · 数学 2024-04-30 Leandro Fiorini Aurichi , Lucas Real

This survey/expository article covers a variety of topics related to the "topology at infinity" of noncompact manifolds and complexes. In manifold topology and geometric group theory, the most important noncompact spaces are often…

几何拓扑 · 数学 2021-03-02 Craig R. Guilbault

Infinite graphs are finitary in the sense that their points are connected via finite paths. So what would an infinitary generalization of finite graphs look like? Usually this question is answered with the aid of topology, e.g. in the case…

组合数学 · 数学 2020-07-21 Hendrik Heine

End-periodic homotopy equivalences of infinite, locally finite graphs serve as dimension-one analogs of the end-periodic automorphisms traditionally defined on infinite-type surfaces. We demonstrate that if $\Gamma$ is an infinite graph…

几何拓扑 · 数学 2025-11-20 Adam R. Smith
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