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We give a constructive proof of the fact that the treewidth of a graph $G$ is bounded by a linear function of the separation number of $G$.

Combinatorics · Mathematics 2025-03-24 Hussein Houdrouge , Babak Miraftab , Pat Morin

Tree-width and path-width are well-known graph parameters. Many NP-hard graph problems allow polynomial-time solutions, when restricted to graphs of bounded tree-width or bounded path-width. In this work, we study the behavior of tree-width…

Data Structures and Algorithms · Computer Science 2024-06-14 Frank Gurski , Robin Weishaupt

Phylogenetic trees and networks are leaf-labelled graphs used to model evolution. Display graphs are created by identifying common leaf labels in two or more phylogenetic trees or networks. The treewidth of such graphs is bounded as a…

Data Structures and Algorithms · Computer Science 2018-09-05 Remie Janssen , Mark Jones , Steven Kelk , Georgios Stamoulis , Taoyang Wu

Graphs on integer points of polytopes whose edges come from a set of allowed differences are studied. It is shown that any simple graph can be embedded in that way. The minimal dimension of such a representation is the fiber dimension of…

Combinatorics · Mathematics 2016-01-19 Tobias Windisch

We study the problem of low-stretch spanning trees in graphs of bounded width: bandwidth, cutwidth, and treewidth. We show that any simple connected graph $G$ with a linear arrangement of bandwidth $b$ can be embedded into a distribution…

Data Structures and Algorithms · Computer Science 2020-04-20 Glencora Borradaile , Erin Wolf Chambers , David Eppstein , William Maxwell , Amir Nayyeri

We show that many graphs with bounded treewidth can be described as subgraphs of the strong product of a graph with smaller treewidth and a bounded-size complete graph. To this end, define the "underlying treewidth" of a graph class…

The number of spanning trees in a graph $G$ is the total number of distinct spanning subgraphs of $G$ that are trees. In this paper we characterize the unique graph with a prescribed vertex (resp. edge) connectivity, minimum degree and…

Combinatorics · Mathematics 2025-12-16 Shaohan Xu , Kexiang Xu , Ivan Damnjanović

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 give a proof for sharp estimate for the number of spanning trees using linear algebra and generalize this bound to multigraphs. In addition, we show that this bound is tight for complete graphs. In addition, we give estimates for number…

Combinatorics · Mathematics 2022-12-01 K. V. Chelpanov

We define a new graph invariant called the scramble number. We show that the scramble number of a graph is a lower bound for the gonality and an upper bound for the treewidth. Unlike the treewidth, the scramble number is not minor monotone,…

Combinatorics · Mathematics 2021-11-08 Michael Harp , Elijah Jackson , David Jensen , Noah Speeter

We compute the treewidth of a family of graphs we refer to as the glued grids, consisting of the stacked prism graphs and the toroidal grids. Our main technique is constructing strict brambles of large orders. We discuss connections to…

Combinatorics · Mathematics 2019-11-05 Ivan Aidun , Frances Dean , Ralph Morrison , Teresa Yu , Julie Yuan

The \emph{linear vertex arboricity} of a graph is the smallest number of sets into which the vertices of a graph can be partitioned so that each of these sets induces a linear forest. Chaplick et al. [JoCG 2020] showed that, somewhat…

Computational Complexity · Computer Science 2025-05-27 Alexander Erhardt , Alexander Wolff

Graph embedding, especially as a subgraph of a grid, is an old topic in VLSI design and graph drawing. In this paper, we investigate related questions concerning the complexity of embedding a graph $G$ in a host graph that is the strong…

Computational Geometry · Computer Science 2026-01-21 Therese Biedl , David Eppstein , Torsten Ueckerdt

We describe a polynomial-time algorithm which, given a graph $G$ with treewidth $t$, approximates the pathwidth of $G$ to within a ratio of $O(t\sqrt{\log t})$. This is the first algorithm to achieve an $f(t)$-approximation for some…

Data Structures and Algorithms · Computer Science 2023-03-13 Carla Groenland , Gwenaël Joret , Wojciech Nadara , Bartosz Walczak

The treewidth is a structural parameter that measures the tree-likeness of a graph. Many algorithmic and combinatorial results are expressed in terms of the treewidth. In this paper, we study the treewidth of outer $k$-planar graphs, that…

Discrete Mathematics · Computer Science 2025-04-24 Oksana Firman , Grzegorz Gutowski , Myroslav Kryven , Yuto Okada , Alexander Wolff

Treewidth is arguably the most important structural graph parameter leading to algorithmically beneficial graph decompositions. Triggered by a strongly growing interest in temporal networks (graphs where edge sets change over time), we…

Data Structures and Algorithms · Computer Science 2020-04-29 Till Fluschnik , Hendrik Molter , Rolf Niedermeier , Malte Renken , Philipp Zschoche

A graph $H$ is an induced subgraph of a graph $G$ if a graph isomorphic to $H$ can be obtained from $G$ by deleting vertices. Recently, there has been significant interest in understanding the unavoidable induced subgraphs for graphs of…

Combinatorics · Mathematics 2022-07-01 Robert Hickingbotham

Square grids play a pivotal role in Robertson and Seymour's work on graph minors as planar obstructions to small treewidth. We introduce a three-sided bramble in a plane graph called a net, which generalizes the standard bramble of crosses…

Combinatorics · Mathematics 2017-06-28 Karen L. Collins , Brett C. Smith

A vertex of degree one in a tree is called an end vertex and a vertex of degree at least three is called a branch vertex. For a graph $G$, let $\sigma_2$ be the minimum degree sum of two nonadjacent vertices in $G$. We consider tree…

Combinatorics · Mathematics 2015-05-19 Zhora Nikoghosyan

A graph $G$ contains a graph $H$ as an induced minor if $H$ can be obtained from $G$ after vertex deletions and edge contractions. We show that for every $k$-vertex planar graph $H$, every graph $G$ excluding $H$ as an induced minor and…

Combinatorics · Mathematics 2024-07-23 Édouard Bonnet , Jędrzej Hodor , Tuukka Korhonen , Tomáš Masařík