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The branchwidth of a graph has been introduced by Roberson and Seymour as a measure of the tree-decomposability of a graph, alternative to treewidth. Branchwidth is polynomially computable on planar graphs by the celebrated ``Ratcatcher''…

Combinatorics · Mathematics 2026-01-29 Dimitrios M. Thilikos , Sebastian Wiederrecht

For their famous algorithm for the disjoint paths problem, Robertson and Seymour proved that there is a function $f$ such that if the tree-width of a graph $G$ with $k$ pairs of terminals is at least $f(k)$, then $G$ contains a…

Discrete Mathematics · Computer Science 2019-01-15 Isolde Adler , Philipp Klaus Krause

A circle graph is an intersection graph of a set of chords of a circle. We describe the unavoidable induced subgraphs of circle graphs with large treewidth. This includes examples that are far from the `usual suspects'. Our results imply…

Combinatorics · Mathematics 2022-12-23 Robert Hickingbotham , Freddie Illingworth , Bojan Mohar , David R. Wood

We show that problems which have finite integer index and satisfy a requirement we call treewidth-bounding admit linear kernels on the class of $H$-topological-minor free graphs, for an arbitrary fixed graph $H$. This builds on earlier…

Data Structures and Algorithms · Computer Science 2012-07-16 Alexander Langer , Felix Reidl , Peter Rossmanith , Somnath Sikdar

The linear arboricity la(G) of a graph G is the minimum number of linear forests that partition the edges of G. In 1984, Akiyama et al. stated the Linear Arboricity Conjecture (LAC), that the linear arboricity of any simple graph of maximum…

Combinatorics · Mathematics 2012-09-06 Marek Cygan , Lukasz Kowalik , Borut Luzar

A random rooted graph is said to be sofic if it is the Benjamini-Schramm limit of a sequence of finite graphs. Given any finite graph $H$, we prove that every one-ended, unimodular random rooted graph that does not have H as a minor must be…

Combinatorics · Mathematics 2025-10-14 Oriol Solé-Pi

We prove a robust contraction decomposition theorem for $H$-minor-free graphs, which states that given an $H$-minor-free graph $G$ and an integer $p$, one can partition in polynomial time the vertices of $G$ into $p$ sets $Z_1,\dots,Z_p$…

Data Structures and Algorithms · Computer Science 2024-12-06 Sayan Bandyapadhyay , William Lochet , Daniel Lokshtanov , Dániel Marx , Pranabendu Misra , Daniel Neuen , Saket Saurabh , Prafullkumar Tale , Jie Xue

In this paper we extend the theory of bidimensionality to two families of graphs that do not exclude fixed minors: map graphs and power graphs. In both cases we prove a polynomial relation between the treewidth of a graph in the family and…

Discrete Mathematics · Computer Science 2007-05-23 Erik D. Demaine , MohammadTaghi Hajiaghayi

The bandwidth theorem [Mathematische Annalen, 343(1):175--205, 2009] states that any $n$-vertex graph $G$ with minimum degree $\big(\tfrac{k-1}{k}+o(1)\big)n$ contains all $n$-vertex $k$-colourable graphs $H$ with bounded maximum degree and…

Combinatorics · Mathematics 2020-05-13 Peter Allen , Julia Böttcher , Julia Ehrenmüller , Anusch Taraz

The $\textit{planar slope number}$ $psn(G)$ of a planar graph $G$ is the minimum number of edge slopes in a planar straight-line drawing of $G$. It is known that $psn(G) \in O(c^\Delta)$ for every planar graph $G$ of maximum degree…

Computational Geometry · Computer Science 2023-11-29 Steven Chaplick , Giordano Da Lozzo , Emilio Di Giacomo , Giuseppe Liotta , Fabrizio Montecchiani

We study a conjecture due to Dallard, Krnc, Kwon, Milani\v{c}, Munaro, \v{S}torgel, and Wiederrecht stating that for any positive integer $d$ and any planar graph $H$, the class of all $K_{1,d}$-free graphs without $H$ as an induced minor…

Combinatorics · Mathematics 2025-06-11 Mujin Choi , Claire Hilaire , Martin Milanič , Sebastian Wiederrecht

A graph coloring has bounded clustering if each monochromatic component has bounded size. This paper studies such a coloring, where the number of colors depends on an excluded complete bipartite subgraph. This is a much weaker assumption…

Combinatorics · Mathematics 2022-09-29 Chun-Hung Liu , David R. Wood

It was proved by Huynh, Mohar, \v{S}\'amal, Thomassen and Wood in 2021 that any countable graph containing every countable planar graph as a subgraph has an infinite clique minor. We prove a finite, quantitative version of this result: for…

At the core of the Robertson-Seymour theory of graph minors lies a powerful structure theorem which captures, for any fixed graph H, the common structural features of all the graphs not containing H as a minor. Robertson and Seymour prove…

Combinatorics · Mathematics 2011-12-13 R. Diestel , K. Kawarabayashi , T. Müller , P. Wollan

An ordered graph is a graph with a linear ordering on its vertex set. We prove that for every positive integer $k$, there exists a constant $c_k>0$ such that any ordered graph $G$ on $n$ vertices with the property that neither $G$ nor its…

Combinatorics · Mathematics 2020-04-10 János Pach , István Tomon

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

Let $G$ be an undirected graph. We say that $G$ contains a ladder of length $k$ if the $2 \times (k+1)$ grid graph is an induced subgraph of $G$ that is only connected to the rest of $G$ via its four cornerpoints. We prove that if all the…

Combinatorics · Mathematics 2024-01-31 Steven Chaplick , Steven Kelk , Ruben Meuwese , Matus Mihalak , Georgios Stamoulis

The bidimensionality of a set of vertices $X$ in a graph $G$ is the maximum $k$ for which $G$ contains as a $X$-rooted minor the $(k \times k)$-grid. This notion allows for the following version of the Graph Minors Structure Theorem (GMST)…

Combinatorics · Mathematics 2026-05-27 Dimitrios M. Thilikos , Sebastian Wiederrecht

We introduce H-clique-width, a new structural measure of graphs that aims to provide a hereditary analogue of the traditional graph product structure. The definition naturally generalises the ordinary clique-width concept. As a result, for…

Combinatorics · Mathematics 2026-05-08 Petr Hliněný , Jan Jedelský

Product structure theorems are a collection of recent results that have been used to resolve a number of longstanding open problems on planar graphs and related graph classes. One particularly useful version states that every planar graph…

Combinatorics · Mathematics 2024-06-17 Vida Dujmović , Gwenaël Joret , Piotr Micek , Pat Morin , David R. Wood