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Related papers: Canonical graph decompositions via coverings

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We introduce torsoids, a canonical structure in matching covered graphs, corresponding to the bricks and braces of the graph. This allows a more fine-grained understanding of the structure of finite and infinite directed graphs with respect…

Combinatorics · Mathematics 2023-05-17 Nathan Bowler , Florian Gut , Meike Hatzel , Ken-ichi Kawarabayashi , Irene Muzi , Florian Reich

Tangles of graphs have been introduced by Robertson and Seymour in the context of their graph minor theory. Tangles may be viewed as describing "k-connected components" of a graph (though in a twisted way). They play an important role in…

Discrete Mathematics · Computer Science 2016-03-03 Martin Grohe , Pascal Schweitzer

We prove that Graph Isomorphism and Canonization in graphs excluding a fixed graph $H$ as a minor can be solved by an algorithm working in time $f(H)\cdot n^{O(1)}$, where $f$ is some function. In other words, we show that these problems…

Data Structures and Algorithms · Computer Science 2022-10-27 Daniel Lokshtanov , Marcin Pilipczuk , Michał Pilipczuk , Saket Saurabh

Baker devised a powerful technique to obtain approximation schemes for various problems restricted to planar graphs. Her technique can be directly extended to various other graph classes, among the most general ones the graphs avoiding a…

Discrete Mathematics · Computer Science 2017-04-04 Zdeněk Dvořák

Decomposing a graph into a hierarchical structure via $k$-core analysis is a standard operation in any modern graph-mining toolkit. $k$-core decomposition is a simple and efficient method that allows to analyze a graph beyond its mere…

Data Structures and Algorithms · Computer Science 2020-01-16 Nikolaj Tatti

We show that all the tangles in a finite graph or matroid can be distinguished by a single tree-decomposition that is invariant under the automorphisms of the graph or matroid. This comes as a corollary of a similar decomposition theorem…

Combinatorics · Mathematics 2017-04-19 Reinhard Diestel , Fabian Hundertmark , Sahar Lemanczyk

A paradigm that was successfully applied in the study of both pure and algorithmic problems in graph theory can be colloquially summarized as stating that "any graph is close to being the disjoint union of expanders". Our goal in this paper…

Combinatorics · Mathematics 2015-02-03 Guy Moshkovitz , Asaf Shapira

This paper is intended as an introductory survey of a newly emerging field: a topological approach to the study of locally finite graphs that crucially incorporates their ends. Topological arcs and circles, which may pass through ends,…

Combinatorics · Mathematics 2012-07-11 Reinhard Diestel

We consider infinite connected quasi-transitive locally finite graphs and show that every such graph with more than one end is a tree amalgamation of two other such graphs. This can be seen as a graph-theoretical version of Stallings'…

Combinatorics · Mathematics 2019-06-19 Matthias Hamann , Florian Lehner , Babak Miraftab , Tim Rühmann

Canonical extension of finitary ordered structures such as lattices, posets, proximity lattices, etc., is a certain completion which entirely describes the topological dual of the ordered structure and it does so in a purely algebraic and…

Category Theory · Mathematics 2022-05-12 Tomáš Jakl

An infinite graph is quasi-transitive if its vertex set has finitely many orbits under the action of its automorphism group. In this paper we obtain a structure theorem for locally finite quasi-transitive graphs avoiding a minor, which is…

Combinatorics · Mathematics 2024-09-13 Louis Esperet , Ugo Giocanti , Clément Legrand-Duchesne

We give a short proof that every finite graph (or matroid) has a tree-decomposition that displays all maximal tangles. This theorem for graphs is a central result of the graph minors project of Robertson and Seymour and the extension to…

Combinatorics · Mathematics 2016-06-01 Johannes Carmesin

A graph $G$ is said to be ubiquitous, if every graph $\Gamma$ that contains arbitrarily many disjoint $G$-minors automatically contains infinitely many disjoint $G$-minors. The well-known Ubiquity conjecture of Andreae says that every…

A graph is locally irregular if any pair of adjacent vertices have distinct degrees. A locally irregular decomposition of a graph $G$ is a decomposition $\mathcal{D}$ of $G$ such that every subgraph $H \in \mathcal{D}$ is locally irregular.…

Combinatorics · Mathematics 2019-02-05 Carla Negri Lintzmayer , Guilherme Oliveira Mota , Maycon Sambinelli

It is shown that a flat subgroup, $H$, of the totally disconnected, locally compact group $G$ decomposes into a finite number of subsemigroups on which the scale function is multiplicative. The image, $P$, of a multiplicative semigroup in…

Group Theory · Mathematics 2017-10-03 Cheryl E. Praeger , Jacqui Ramagge , George Willis

We show that an arbitrary infinite graph $G$ can be compactified by its ends plus its critical vertex sets, where a finite set $X$ of vertices of an infinite graph is critical if its deletion leaves some infinitely many components each with…

Combinatorics · Mathematics 2018-04-03 Jan Kurkofka , Max Pitz

Random intersection graphs model networks with communities, assuming an underlying bipartite structure of groups and individuals, where these groups may overlap. Group memberships are generated through the bipartite configuration model.…

Probability · Mathematics 2026-01-14 Remco van der Hofstad , Julia Komjathy , Viktoria Vadon

We study edge-decompositions of highly connected graphs into copies of a given tree. In particular we attack the following conjecture by Bar\'at and Thomassen: for each tree $T$, there exists a natural number $k_T$ such that if $G$ is a…

Combinatorics · Mathematics 2012-03-09 János Barát , Dániel Gerbner

Carmesin and Gollin proved that every finite graph has a canonical tree-decomposition $(T, \mathcal{V})$ of adhesion less than $k$ that efficiently distinguishes every two distinct $k$-profiles, and which has the further property that every…

Combinatorics · Mathematics 2024-03-29 Sandra Albrechtsen

Inspired by decomposition problems in rule-based formalisms in Computational Systems Biology and recent work on compositionality in graph transformation, this paper proposes to use arbitrary colimits to "deconstruct" models of reactions in…

Logic in Computer Science · Computer Science 2010-08-13 Tobias Heindel