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Related papers: Path decompositions of Eulerian graphs

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Dumas, Foucaud, Perez, and Todinca [SIAM J. Disc. Math., 2024] proved that if the vertex set of a graph $G$ can be covered by $k$ shortest paths, then the pathwidth of $G$ is bounded by $\mathcal{O}(k \cdot 3^k)$. We prove a coarse variant…

Combinatorics · Mathematics 2025-03-05 Meike Hatzel , Michał Pilipczuk

Given a graph $G$ and $\mathcal{A}\subseteq V(G)$, a classical theorem of Gallai (1964) states that for every positive integer $k$, the graph $G$ contains $k$ pairwise vertex-disjoint $\mathcal{A}$-paths, or a set $Z\subseteq V(G)$ of size…

Combinatorics · Mathematics 2025-12-22 Robert Hickingbotham , Gwenaël Joret

Given a graph $G$, a decomposition of $G$ is a partition of its edges. A graph is $(d, h)$-decomposable if its edge set can be partitioned into a $d$-degenerate graph and a graph with maximum degree at most $h$. For $d \le 4$, we are…

Combinatorics · Mathematics 2020-07-06 Eun-Kyung Cho , Ilkyoo Choi , Ringi Kim , Boram Park , Tingting Shan , Xuding Zhu

Let $G$ be a (multi)graph of order $n$ and let $u,v$ be vertices of $G$. The maximum number of internally disjoint $u$-$v$ paths in $G$ is denoted by $\kappa_G(u,v)$, and the maximum number of edge-disjoint $u$-$v$ paths in $G$ is denoted…

Combinatorics · Mathematics 2018-10-25 Rocío M. Casablanca , Lucas Mol , Ortrud R. Oellermann

Menger's well-known theorem from 1927 characterizes when it is possible to find $k$ vertex-disjoint paths between two sets of vertices in a graph $G$. Recently, Georgakopoulos and Papasoglu and, independently, Albrechtsen, Huynh, Jacobs,…

Combinatorics · Mathematics 2025-01-16 Tung Nguyen , Alex Scott , Paul Seymour

Magnant and Martin conjectured that the vertex set of any $d$-regular graph $G$ on $n$ vertices can be partitioned into $n / (d+1)$ paths (there exists a simple construction showing that this bound would be best possible). We prove this…

Combinatorics · Mathematics 2021-07-01 Vytautas Gruslys , Shoham Letzter

We show that for every l, there exists d_l such that every 3-edge-connected graph with minimum degree d_l can be edge-partitioned into paths of length l (provided that its number of edges is divisible by l). This improves a result asserting…

Combinatorics · Mathematics 2019-07-29 Tereza Klimošová , Stéphan Thomassé

Balogh, Bar\'at, Gerbner, Gy\'arf\'as, and S\'ark\"ozy proposed the following conjecture. Let $G$ be a graph on $n$ vertices with minimum degree at least $3n/4$. Then for every $2$-edge-colouring of $G$, the vertex set $V(G)$ may be…

Combinatorics · Mathematics 2015-02-27 Shoham Letzter

A triangle decomposition of a graph is a partition of its edges into triangles. A fractional triangle decomposition of a graph is an assignment of a non-negative weight to each of its triangles such that the sum of the weights of the…

Combinatorics · Mathematics 2015-07-22 François Dross

Dirac (1952) proved that every connected graph of order $n>2k+1$ with minimum degree more than $k$ contains a path of length at least $2k+1$. Erd\H{o}s and Gallai (1959) showed that every $n$-vertex graph $G$ with average degree more than…

Combinatorics · Mathematics 2024-06-18 Yue Ma , Xinmin Hou , Jun Gao

Let $G$ be a graph of order $n$. The maximum and minimum degree of $G$ are denoted by $\Delta$ and $\delta$ respectively. The \emph{path partition number} $\mu (G)$ of a graph $G$ is the minimum number of paths needed to partition the…

Combinatorics · Mathematics 2022-12-27 M. Kouider , M. Zamime

A $(d,h)$-decomposition of a graph $G$ is an ordered pair $(D, H)$ such that $H$ is a subgraph of $G$ of maximum degree at most $h$ and $D$ is an acyclic orientation of $G-E(H)$ with maximum out-degree at most $d$. In this paper, we prove…

Combinatorics · Mathematics 2023-03-16 Lingxi Li , Huajing Lu , Tao Wang , Xuding Zhu

For a simple graph $G$, let $n$ and $m$ denote the number of vertices and edges in $G$, respectively. The Erd\H{o}s-Gallai theorem for paths states that in a simple $P_k$-free graph, $m \leq \frac{n(k-1)}{2}$, where $P_k$ denotes a path…

Combinatorics · Mathematics 2025-05-08 Rajat Adak , L. Sunil Chandran

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

Let $c\in (0, 1]$ be a real number and let $n$ be a sufficiently large integer. We prove that every $n$-vertex $c n$-regular graph $G$ contains a collection of $\lfloor 1/c \rfloor$ paths whose union covers all but at most $o(n)$ vertices…

Combinatorics · Mathematics 2017-06-22 Jie Han

The detour between two points u and v (on edges or vertices) of an embedded planar graph whose edges are curves is the ratio between the shortest path in in the graph between u and v and their Euclidean distance. The maximum detour over all…

Metric Geometry · Mathematics 2008-01-08 Adrian Dumitrescu , Annette Ebbers-Baumann , Ansgar Grüne , Rolf Klein , Günter Rote

In 2006, Bar\'at and Thomassen posed the following conjecture: for each tree $T$, there exists a natural number $k_T$ such that, if $G$ is a $k_T$-edge-connected graph and $|E(G)|$ is divisible by $|E(T)|$, then $G$ admits a decomposition…

Combinatorics · Mathematics 2015-09-23 Fabio Botler , Guilherme O. Mota , Marcio T. I. Oshiro , Yoshiko Wakabayashi

Mkrtchyan and Steffen [J. Graph Theory, 70 (4), 473--482, 2012] showed that every class II simple graph can be decomposed into a maximum $\Delta$-edge-colorable subgraph and a matching. They further conjectured that every graph $G$ with…

Combinatorics · Mathematics 2022-11-14 Yan Cao , Guangming Jing , Rong Luo , Vahan Mkrtchyan , Cun-Quan Zhang , Yue Zhao

A well-known question of Gallai (1966) asked whether there is a vertex which passes through all longest paths of a connected graph. Although this has been verified for some special classes of graphs such as outerplanar graphs, circular arc…

Combinatorics · Mathematics 2022-01-28 Bing Wei , Haidong Wu , Qinghong Zhao

Motivated by longstanding conjectures regarding decompositions of graphs into paths and cycles, we prove the following optimal decomposition results for random graphs. Let $0<p<1$ be constant and let $G\sim G_{n,p}$. Let $odd(G)$ be the…

Combinatorics · Mathematics 2016-06-21 Stefan Glock , Daniela Kühn , Deryk Osthus