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The Gy\'arf\'as tree packing conjecture asserts that any set of trees with $2,3, ..., k$ vertices has an (edge-disjoint) packing into the complete graph on $k$ vertices. Gy\'arf\'as and Lehel proved that the conjecture holds in some special…

Combinatorics · Mathematics 2011-10-24 Dániel Gerbner , Balázs Keszegh , Cory Palmer

The Tree Decomposition Conjecture by Bar\'at and Thomassen states that for every tree $T$ there exists a natural number $k(T)$ such that the following holds: If $G$ is a $k(T)$-edge-connected simple graph with size divisible by the size of…

Combinatorics · Mathematics 2016-03-02 Martin Merker

A subgraph of an edge-coloured graph is called rainbow if all its edges have distinct colours. The study of rainbow subgraphs goes back more than two hundred years to the work of Euler on Latin squares and has been the focus of extensive…

Combinatorics · Mathematics 2019-04-24 Richard Montgomery , Alexey Pokrovskiy , Benny Sudakov

We show that the complete graph on $n$ vertices can be decomposed into $t$ cycles of specified lengths $m_1,\ldots,m_t$ if and only if $n$ is odd, $3\leq m_i\leq n$ for $i=1,\ldots,t$, and $m_1+\cdots+m_t=\binom n2$. We also show that the…

Combinatorics · Mathematics 2018-05-16 Darryn Bryant , Daniel Horsley , William Pettersson

A $k$-star decomposition of a graph is a partition of its edges into $k$-stars (i.e., $k$ edges with a common vertex). The paper studies the following problem: given $k \leq d/2$, does the random $d$-regular graph have a $k$-star…

Combinatorics · Mathematics 2025-06-13 Viktor Harangi

P. Erd\H{o}s proved that every 2-edge coloured complete graph on the natural numbers can be vertex decomposed into two monochromatic paths of different colour. This result was extended by R. Rado to an arbitrary finite number of colours. We…

Combinatorics · Mathematics 2016-03-17 Daniel T. Soukup

We study the Decomposition Conjecture posed by Bar\'at and Thomassen (2006), which states that for every tree $T$ there exists a natural number $k_T$ such that, if $G$ is a $k_T$-edge-connected graph and $|E(T)|$ divides $|E(G)|$, then $G$…

Combinatorics · Mathematics 2015-07-30 Fábio Botler , Guilherme O. Mota , Marcio T. I. Oshiro , Yoshiko Wakabayashi

A linear forest is a collection of vertex-disjoint paths. The Linear Arboricity Conjecture states that every graph of maximum degree $\Delta$ can be decomposed into at most $\lceil(\Delta+1)/2\rceil$ linear forests. We prove that $\Delta/2…

Combinatorics · Mathematics 2025-07-29 Micha Christoph , Nemanja Draganić , António Girão , Eoin Hurley , Lukas Michel , Alp Müyesser

A $k$-star decomposition of a graph is a partition of its edges into $k$-stars (i.e., $k$ edges with a common vertex). The paper studies the following problem: for what values of $k>d/2$ does the random $d$-regular graph have a $k$-star…

Combinatorics · Mathematics 2025-03-24 Viktor Harangi

An equitable partition of a graph $G$ is a partition of the vertex-set of $G$ such that the sizes of any two parts differ by at most one. We show that every graph with an acyclic coloring with at most $k$ colors can be equitably partitioned…

Combinatorics · Mathematics 2015-04-17 Louis Esperet , Laetitia Lemoine , Frédéric Maffray

Graph isomorphism, subgraph isomorphism, and maximum common subgraphs are classical well-investigated objects. Their (parameterized) complexity and efficiently tractable cases have been studied. In the present paper, for a given set of…

Data Structures and Algorithms · Computer Science 2024-03-22 Dieter Rautenbach , Florian Werner

Wu, Zhang and Li [4] conjectured that the set of vertices of any simple graph $G$ can be equitably partitioned into $\lceil(\Delta(G)+1)/2\rceil$ subsets so that each of them induces a forest of $G$. In this note, we prove this conjecture…

Combinatorics · Mathematics 2012-11-22 Xin Zhang , Jian-Liang Wu

We examine the adjacency spectrum of trees with diameter three, also referred to as double stars. Using $P_2(a,b)$ to denote a double star with $ a$ and $b$ leaves at its respective endpoints, we discuss graphs which are cospectral to…

Combinatorics · Mathematics 2025-06-10 Emily Barranca , Michael D. Barrus

In 1979 Tarsi showed that an edge decomposition of a complete multigraph into stars of size $m$ exists whenever some obvious necessary conditions hold. In 1992 Lonc gave necessary and sufficient conditions for the existence of an edge…

Combinatorics · Mathematics 2020-06-02 Rosalind A. Cameron , Daniel Horsley

Tibor Gallai conjectured that the edge set of every connected graph $G$ on $n$ vertices can be partitioned into $\lceil n/2\rceil$ paths. Let $\mathcal{G}_{k}$ be the class of all $2k$-regular graphs of girth at least $2k-2$ that admit a…

Discrete Mathematics · Computer Science 2015-10-12 Fábio Botler , Andrea Jiménez

Gallai's conjecture asserts that every connected graph on $n$ vertices can be decomposed into $\frac{n+1}{2}$ paths. For general graphs (possibly disconnected), it was proved that every graph on $n$ vertices can be decomposed into…

Combinatorics · Mathematics 2025-10-16 Yanan Chu , Yan Wang

A graph is 2-degenerate if every subgraph contains a vertex of degree at most 2. We show that every 2-degenerate graph can be drawn with straight lines such that the drawing decomposes into 4 plane forests. Therefore, the geometric…

Combinatorics · Mathematics 2023-03-01 Rahul Jain , Marco Ricci , Jonathan Rollin , André Schulz

We investigate the tractability of a simple fusion of two fundamental structures on graphs, a spanning tree and a perfect matching. Specifically, we consider the following problem: given an edge-weighted graph, find a minimum-weight…

Data Structures and Algorithms · Computer Science 2024-07-12 Kristóf Bérczi , Tamás Király , Yusuke Kobayashi , Yutaro Yamaguchi , Yu Yokoi

Given a graph $G=(V,E)$ with arboricity $\alpha$, we study the problem of decomposing the edges of $G$ into $(1+\epsilon)\alpha$ disjoint forests in the distributed LOCAL model. Barenboim and Elkin [PODC `08] gave a LOCAL algorithm that…

Data Structures and Algorithms · Computer Science 2023-10-13 David G. Harris , Hsin-Hao Su , Hoa T. Vu

In [W. Mader, Connectivity keeping paths in $k$-connected graphs, J. Graph Theory 65 (2010) 61-69.], Mader conjectured that for every positive integer $k$ and every finite tree $T$ with order $m$, every $k$-connected, finite graph $G$ with…

Combinatorics · Mathematics 2017-07-26 Yingzhi Tian , Jixiang Meng , Hong-Jian Lai , Liqiong Xu