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Related papers: On graphs coverable by chubby shortest paths

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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 show that if the edges or vertices of an undirected graph $G$ can be covered by $k$ shortest paths, then the pathwidth of $G$ is upper-bounded by a single-exponential function of $k$. As a corollary, we prove that the problem Isometric…

Discrete Mathematics · Computer Science 2025-10-13 Maël Dumas , Florent Foucaud , Anthony Perez , Ioan Todinca

We study a large family of graph covering problems, whose definitions rely on distances, for graphs of bounded cyclomatic number (that is, the minimum number of edges that need to be removed from the graph to destroy all cycles). These…

Discrete Mathematics · Computer Science 2025-09-03 Dibyayan Chakraborty , Florent Foucaud , Anni Hakanen

A connected subgraph of a graph is isometric if it preserves distances. In this short note, we provide counterexamples to several variants of the following general question: When a graph $G$ is edge covered by connected isometric subgraphs…

Combinatorics · Mathematics 2025-11-06 Paul Bastide , Julien Duron , Jędrzej Hodor , Weichan Liu , Xiangxiang Nie

We provide a degree condition on a regular $n$-vertex graph $G$ which ensures the existence of a near optimal packing of any family $\mathcal H$ of bounded degree $n$-vertex $k$-chromatic separable graphs into $G$. In general, this degree…

Combinatorics · Mathematics 2018-11-12 Padraig Condon , Jaehoon Kim , Daniela Kühn , Deryk Osthus

We investigate the minimum line-distortion and the minimum bandwidth problems on unweighted graphs and their relations with the minimum length of a Robertson-Seymour's path-decomposition. The length of a path-decomposition of a graph is the…

Data Structures and Algorithms · Computer Science 2014-10-01 Feodor F. Dragan , Ekkehard Köhler , Arne Leitert

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

It is easy to see that in a connected graph any 2 longest paths have a vertex in common. For k>=7, Skupien in [7] obtained a connected graph in which some k longest paths have no common vertex, but every k-1 longest paths have a common…

Combinatorics · Mathematics 2018-05-04 Jan Ekstein , Shinya Fujita , Adam Kabela , Jakub Teska

We consider the problem of partitioning the edges of a graph into as few paths as possible. This is a~subject of the classic conjecture of Gallai and a recurring topic in combinatorics. Regarding the complexity of partitioning a graph…

Data Structures and Algorithms · Computer Science 2026-02-16 Tomáš Masařík , Michał Włodarczyk , Mehmet Akif Yıldız

We consider a bi-criteria generalization of the pathwidth problem, where, for given integers $k,l$ and a graph $G$, we ask whether there exists a path decomposition $\cP$ of $G$ such that the width of $\cP$ is at most $k$ and the number of…

Data Structures and Algorithms · Computer Science 2021-03-05 Dariusz Dereniowski , Wieslaw Kubiak , Yori Zwols

A graph $G$ is $k$-path-coverable if its vertex set $V(G)$ can be covered by $k$ or fewer vertex disjoint paths. In this paper, using the $Q$-index of a connected graph $G$, we present a tight sufficient condition for $G$ with fixed minimum…

Combinatorics · Mathematics 2021-09-16 Tao Cheng , Lihua Feng , Yongtao Li , Weijun Liu

It is an easy observation that if a graph~$G$ admits a path-decomposition whose parts have small radius, then $G$ contains no large subdivision of $K_{1,3}$ or $K^3$ as a (quasi-)geodesic subgraph. We show that these are in fact the only…

A well known theorem in graph theory states that every graph $G$ on $n$ vertices and minimum degree at least $d$ contains a path of length at least $d$, and if $G$ is connected and $n\ge 2d+1$ then $G$ contains a path of length at least…

Combinatorics · Mathematics 2019-03-12 Yue Ma , Xinmin Hou , Jun Gao

Linear rank-width is a graph width parameter, which is a variation of rank-width by restricting its tree to a caterpillar. As a corollary of known theorems, for each $k$, there is a finite obstruction set $\mathcal{O}_k$ of graphs such that…

Combinatorics · Mathematics 2014-09-10 Jisu Jeong , O-joung Kwon , Sang-il Oum

For an integer $k \ge 1$, a (distance) $k$-dominating set of a connected graph $G$ is a set $S$ of vertices of $G$ such that every vertex of $V(G) \setminus S$ is at distance at most~$k$ from some vertex of $S$. The $k$-domination number,…

Combinatorics · Mathematics 2015-08-03 Randy Davila , Caleb Fast , Michael Henning , Franklin Kenter

A subset S of vertices of a graph G is called a k-path vertex cover if every path of order k in G contains at least one vertex from S. Denote by \psi_k(G) the minimum cardinality of a k-path vertex cover in G. It is shown that the problem…

Combinatorics · Mathematics 2011-08-02 Boštjan Brešar , František Kardoš , Ján Katrenič , Gabriel Semanišin

For an integer $k\ge 3$, a $k$-path vertex cover of a graph $G=(V,E)$ is a set $T\subseteq V$ that shares a vertex with every path subgraph of order $k$ in $G$. The minimum cardinality of a $k$-path vertex cover is denoted by $\psi_k(G)$.…

Combinatorics · Mathematics 2021-05-06 Csilla Bujtás , Marko Jakovac , Zsolt Tuza

A set $S$ of isometric paths of a graph $G$ is ``$v$-rooted'', where $v$ is a vertex of $G$, if $v$ is one of the endpoints of all the isometric paths in $S$. The isometric path complexity of a graph $G$, denoted by $ipco{G}$, is the…

Combinatorics · Mathematics 2025-09-03 Dibyayan Chakraborty , Jérémie Chalopin , Florent Foucaud , Yann Vaxès

We described a simple algorithm running in linear time for each fixed constant $k$, that either establishes that the pathwidth of a graph $G$ is greater than $k$, or finds a path-decomposition of $G$ of width at most $O(2^{k})$. This…

Combinatorics · Mathematics 2009-09-25 Kevin Cattell , Michael J. Dinneen , Michael R. Fellows

A subset $S$ of vertices of a graph $G=(V,E)$ is called a $k$-path vertex cover if every path on $k$ vertices in $G$ contains at least one vertex from $S$. Denote by $\psi_k(G)$ the minimum cardinality of a $k$-path vertex cover in $G$ and…

Combinatorics · Mathematics 2016-02-18 Sławomir Bakalarski , Jakub Zygadło
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