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Related papers: A shorter proof of the path-width theorem

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A graph has tree-width at most $k$ if it can be obtained from a set of graphs each with at most $k+1$ vertices by a sequence of clique sums. We refine this definition by, for each non-negative integer $\theta$, defining the…

Combinatorics · Mathematics 2016-09-30 Jim Geelen , Benson Joeris

We prove that if a graph has a tree-decomposition of width at most w, then it has a tree-decomposition of width at most w with certain desirable properties. We will use this result in a subsequent paper to show that every 2-connected graph…

Combinatorics · Mathematics 2018-04-17 Thanh N. Dang , Robin Thomas

Many of the tools developed for the theory of tree-decompositions of graphs do not work for directed graphs. In this paper we show that some of the most basic tools do work in the case where the model digraph is a directed path. Using these…

Combinatorics · Mathematics 2017-11-03 Joshua Erde

Diestel and M\"uller showed that the connected tree-width of a graph $G$, i.e., the minimum width of any tree-decomposition with connected parts, can be bounded in terms of the tree-width of $G$ and the largest length of a geodesic cycle in…

Combinatorics · Mathematics 2017-02-15 Matthias Hamann , Daniel Weißauer

Dumas, Foucaud, Perez and Todinca (2024) recently proved that every graph whose edges can be covered by $k$ shortest paths has pathwidth at most $O(3^k)$. In this paper, we improve this upper bound on the pathwidth to a polynomial one;…

Combinatorics · Mathematics 2026-02-27 Julien Baste , Lucas De Meyer , Ugo Giocanti , Etienne Objois , Timothé Picavet

We prove that every graph of rank-width $k$ is a pivot-minor of a graph of tree-width at most $2k$. We also prove that graphs of rank-width at most 1, equivalently distance-hereditary graphs, are exactly vertex-minors of trees, and graphs…

Combinatorics · Mathematics 2014-03-26 O-joung Kwon , Sang-il Oum

The pathwidth of a graph $G$ is the smallest $w\in \mathbb{N}$ such that $G$ can be constructed from a sequence of graphs, each on at most $w+1$ vertices, by gluing them together in a linear fashion. We provide a full classification of the…

Combinatorics · Mathematics 2024-12-30 Maria Chudnovsky , Sepehr Hajebi , Sophie Spirkl

Nancy G. Kinnersley and Michael A. Langston has determined the excluded minors for the class of graphs with path-width at most two by computer. Their list consisted of 110 graphs. Such a long list is difficult to handle and gives no insight…

Combinatorics · Mathematics 2009-10-27 János Barát , Péter Hajnal , Yixun Lin , Aifeng Yang

Let $P$ be a graph with a vertex $v$ such that $P\backslash v$ is a forest, and let $Q$ be an outerplanar graph. We prove that there exists a number $p=p(P,Q)$ such that every 2-connected graph of path-width at least $p$ has a minor…

Combinatorics · Mathematics 2018-04-17 Thanh N. Dang , Robin Thomas

We prove that, for every $k=1,2,...,$ every shortest-path metric on a graph of pathwidth $k$ embeds into a distribution over random trees with distortion at most $c$ for some $c=c(k)$. A well-known conjecture of Gupta, Newman, Rabinovich,…

Metric Geometry · Mathematics 2012-10-09 James R. Lee , Anastasios Sidiropoulos

One of the major results of [N. Robertson and P. D. Seymour. Graph minors. XIII. The disjoint paths problem. J. Combin. Theory Ser. B, 63(1):65--110, 1995], also known as the weak structure theorem, revealed the local structure of graphs…

Combinatorics · Mathematics 2011-03-01 Archontia C. Giannopoulou , Dimitrios M. Thilikos

We prove that a minor-closed class of graphs has bounded layered pathwidth if and only if some apex-forest is not in the class. This generalises a theorem of Robertson and Seymour, which says that a minor-closed class of graphs has bounded…

Combinatorics · Mathematics 2020-08-03 Vida Dujmović , David Eppstein , Gwenaël Joret , Pat Morin , David R. Wood

Graphs with bounded treewidth and bounded maximum degree are known to have tree-partitions of bounded width. What can be said if the bounded treewidth assumption is strengthened to bounded pathwidth? We prove that every graph with bounded…

Combinatorics · Mathematics 2026-05-28 David R. Wood

Given a connected graph $G=(V(G), E(G))$, the length of a shortest path from a vertex $u$ to a vertex $v$ is denoted by $d(u,v)$. For a proper subset $W$ of $V(G)$, let $m(W)$ be the maximum value of $d(u,v)$ as $u$ ranging over $W$ and $v$…

Combinatorics · Mathematics 2021-01-11 Min Feng , Xuanlong Ma , Huiling Xu

Birmele [J. Graph Theory, 2003] proved that every graph with circumference t has treewidth at most t-1. Under the additional assumption of 2-connectivity, such graphs have bounded pathwidth, which is a qualitatively stronger result.…

Combinatorics · Mathematics 2015-06-08 Emily A. Marshall , David R. Wood

Courcelle's Theorem is an important result in graph theory, proving the existence of linear-time algorithms for many decision problems on graphs whose tree-width is bounded by a constant. The purpose of this text is twofold: to provide an…

Combinatorics · Mathematics 2024-05-03 Adrian Rettich

We prove that a connected graph has linear rank-width 1 if and only if it is a distance-hereditary graph and its split decomposition tree is a path. An immediate consequence is that one can decide in linear time whether a graph has linear…

Discrete Mathematics · Computer Science 2014-07-09 Binh-Minh Bui-Xuan , Mamadou Moustapha Kanté , Vincent Limouzy

In the first paper of the Graph Minors series [JCTB '83], Robertson and Seymour proved the Forest Minor theorem: the $H$-minor-free graphs have bounded pathwidth if and only if $H$ is a forest. In recent years, considerable effort has been…

Combinatorics · Mathematics 2025-12-02 Édouard Bonnet , Benjamin Duhamel , Robert Hickingbotham

Motivated by an old question of Gallai (1966) on the intersection of longest paths in a graph and the well-known conjectures of Lov\'{a}sz (1969) and Thomassen (1978) on the maximum length of paths and cycles in vertex-transitive graphs, we…

Combinatorics · Mathematics 2025-08-05 Sergey Norin , Raphael Steiner , Stephan Thomassé , Paul Wollan

We prove that, if $m$ is sufficiently large, every graph on $m+1$ vertices that has a universal vertex and minimum degree at least $\lfloor \frac{2m}{3} \rfloor$ contains each tree $T$ with $m$ edges as a subgraph. Our result confirms, for…

Combinatorics · Mathematics 2022-07-21 Bruce Reed , Maya Stein
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