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Related papers: On treewidth and maximum cliques

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We present a hereditary class of graphs of unbounded clique-width which is well-quasi-ordered by the induced subgraph relation. This result provides a negative answer to the question asked by Daligault, Rao and Thomass\'e in…

Discrete Mathematics · Computer Science 2015-03-03 Vadim Lozin , Igor Razgon , Viktor Zamaraev

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

A theta is a graph consisting of two non-adjacent vertices and three internally disjoint paths between them, each of length at least two. For a family $\mathcal{H}$ of graphs, we say a graph $G$ is $\mathcal{H}$-free if no induced subgraph…

Combinatorics · Mathematics 2022-09-09 Tara Abrishami , Maria Chudnovsky , Sepehr Hajebi , Sophie Spirkl

We prove that for every integer $t\geq 1$ there exists an integer $c_t\geq 1$ such that every $n$-vertex even-hole-free graph with no clique of size $t$ has treewidth at most $c_t\log{n}$. This resolves a conjecture of Sintiari and…

Combinatorics · Mathematics 2024-05-07 Maria Chudnovsky , Peter Gartland , Sepehr Hajebi , Daniel Lokshtanov , Sophie Spirkl

We investigate two recently introduced graph parameters, both of which measure the complexity of the tree decompositions of a given graph. Recall that the treewidth ${\rm tw}(G)$ of a graph $G$ measures the largest number of vertices…

Combinatorics · Mathematics 2026-01-21 Alex Koutsoutis , Kilian Krause , Chun-Hung Liu , Mirza Redzic , Torsten Ueckerdt

A conjecture in algorithmic model theory predicts that the model-checking problem for first-order logic is fixed-parameter tractable on a hereditary graph class if and only if the class is monadically dependent. Originating in model theory,…

Combinatorics · Mathematics 2024-03-28 Jan Dreier , Nikolas Mählmann , Szymon Toruńczyk

Barbieri recently showed that the finite graphs realising any given finite automorphism group have unbounded genus, answering a question of Cornwell et al. In this note we give a short proof of a stronger result: they have unbounded clique…

Combinatorics · Mathematics 2025-01-20 John Haslegrave

Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function $f\colon\mathbb{N}\to\mathbb{N}\cup\{\infty\}$ with $f(1)=1$ and $f(n)\geq\binom{3n+1}{3}$, we construct a hereditary class of graphs…

Combinatorics · Mathematics 2023-08-17 Marcin Briański , James Davies , Bartosz Walczak

A hereditary class H of graphs is $\chi$-bounded if there is a $\chi$-binding function f such that for every $G$ in $H$, $\chi(G)$ less than or equal to $f(\omega(G))$. Here we prove that if a graph $G$ is free of 1. {Chair; P$_4$+K$_1$} or…

Combinatorics · Mathematics 2023-12-29 Medha Dhurandhar

Partitioning a graph using graph separators, and particularly clique separators, are well-known techniques to decompose a graph into smaller units which can be treated independently. It was previously known that the treewidth was bounded…

Discrete Mathematics · Computer Science 2019-09-09 Boi Faltings , Martin Charles Golumbic

Truemper configurations (thetas, pyramids, prisms, and wheels) have played an important role in the study of complex hereditary graph classes (e.g. the class of perfect graphs and the class of even-hole-free graphs), appearing both as…

Combinatorics · Mathematics 2017-07-12 Valerio Boncompagni , Irena Penev , Kristina Vuskovic

A graph is chordal if it contains no induced cycle of length four or more. While finite chordal graphs are precisely those admitting tree-decompositions into cliques, this fails for infinite graphs. We establish two results extending the…

Combinatorics · Mathematics 2026-03-26 Max Pitz , Lucas Real , Roman Schaut

We study two graph parameters defined via tree decompositions: tree-independence number and induced matching treewidth. Both parameters are defined similarly as treewidth, but with respect to different measures of a tree decomposition…

Discrete Mathematics · Computer Science 2025-11-07 Noga Alon , Martin Milanič , Paweł Rzążewski

Dvo\v{r}\'ak and Kawarabayashi [European Journal of Combinatorics, 2017] asked, what is the largest chromatic number attainable by a graph of treewidth $t$ with no $K_r$ subgraph? In this paper, we consider the fractional version of this…

Combinatorics · Mathematics 2023-12-19 Peter Bradshaw

The treewidth of a graph is an important invariant in structural and algorithmic graph theory. This paper studies the treewidth of line graphs. We show that determining the treewidth of the line graph of a graph $G$ is equivalent to…

Combinatorics · Mathematics 2014-09-25 Daniel J. Harvey , David R. Wood

Treewidth is a well-known graph invariant with multiple interesting applications in combinatorics. On the practical side, many NP-complete problems are polynomial-time (sometimes even linear-time) solvable on graphs of bounded treewidth. On…

Category Theory · Mathematics 2021-05-13 Zoltan A. Kocsis , Benjamin Merlin Bumpus

A strengthened version of Harborth's well-known conjecture -- known as Kleber's conjecture -- states that every planar graph admits a planar straight-line drawing where every edge has integer length and each vertex is restricted to the…

Computational Geometry · Computer Science 2025-09-05 Henry Förster , Stephen Kobourov , Jacob Miller , Johannes Zink

We introduce the graph theoretical parameter of edge treewidth. This parameter occurs in a natural way as the tree-like analogue of cutwidth or, alternatively, as an edge-analogue of treewidth. We study the combinatorial properties of…

Discrete Mathematics · Computer Science 2021-12-15 Loïc Magne , Christophe Paul , Abhijat Sharma , Dimitrios M. Thilikos

We consider the classical problems (Edge) Steiner Tree and Vertex Steiner Tree after restricting the input to some class of graphs characterized by a small set of forbidden induced subgraphs. We show a dichotomy for the former problem…

Data Structures and Algorithms · Computer Science 2020-12-17 Hans Bodlaender , Nick Brettell , Matthew Johnson , Giacomo Paesani , Daniel Paulusma , Erik Jan van Leeuwen

In this paper we compare and illustrate the algorithmic use of graphs of bounded tree-width and graphs of bounded clique-width. For this purpose we give polynomial time algorithms for computing the four basic graph parameters independence…

Data Structures and Algorithms · Computer Science 2008-12-18 Frank Gurski