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Related papers: On perfect packings in dense graphs

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Let $n \equiv 0\, (\, \text{mod } 3\,)$ and $H_{n, n/3}^2$ be the 3-graph of order $n$, whose vertex set is partitioned into two sets $S$ and $T$ of size $\frac{1}{3}n+1$ and $\frac{2}{3}n -1$, respectively, and whose edge set consists of…

Combinatorics · Mathematics 2024-01-09 Yan Wang , Yi Zhang

We consider the problem of determining the maximum induced density of a graph H in any graph on n vertices. The limit of this density as n tends to infinity is called the inducibility of H. The exact value of this quantity is known only for…

Combinatorics · Mathematics 2013-07-17 James Hirst

Let $H$ be a fixed graph on $v$ vertices. For an $n$-vertex graph $G$ with $n$ divisible by $v$, an $H$-{\em factor} of $G$ is a collection of $n/v$ copies of $H$ whose vertex sets partition $V(G)$. In this paper we consider the threshold…

Combinatorics · Mathematics 2008-03-25 A. Johansson , J. Kahn , V. Vu

A graph is $H$-free if it does not contain an induced subgraph isomorphic to $H$. For every integer $k$ and every graph $H$, we determine the computational complexity of $k$-Edge Colouring for $H$-free graphs.

Data Structures and Algorithms · Computer Science 2018-10-11 Esther Galby , Paloma T. Lima , Daniel Paulusma , Bernard Ries

A matching in a graph $G$ is a set of independent edges in $G$. A perfect matching in a graph $G$ is a matching which saturates all the vertices of $G$. A fractional perfect matching in a graph $G$ is a function $h:E(G)\rightarrow [0,1]$…

Combinatorics · Mathematics 2026-04-08 Sizhong Zhou

A graph $G$ admits an $H$-tiling if it contains a collection of vertex-disjoint copies of $H$. In this paper, we confirm a conjecture proposed by K\"{u}hn, Osthus, and Treglown by showing that for any given graph $H$, there exists a…

Combinatorics · Mathematics 2026-05-25 Yuping Gao , Yilin Guo , Guanghui Wang , Lin-Peng Zhang

In this paper, we generalize the notions of perfect matchings, perfect 2-matchings to perfect k-matchings and give a necessary and sufficient condition for existence of perfect k-matchings. For bipartite graphs, we show that this k-matching…

Combinatorics · Mathematics 2010-08-26 Hongliang Lu

For a graph $F$, we say that another graph $G$ is $F$-saturated, if $G$ is $F$-free and adding any edge to $G$ would create a copy of $F$. We study for a given graph $F$ and integer $n$ whether there exists a regular $n$-vertex…

Combinatorics · Mathematics 2020-12-22 Dániel Gerbner , Balázs Patkós , Zsolt Tuza , Máté Vizer

Two graphs $G_1$ and $G_2$ on $n$ vertices are said to pack if there exist injective mappings of their vertex sets into $[n]$ such that the images of their edge sets are disjoint. A longstanding conjecture due to Bollob\'as and Eldridge…

Combinatorics · Mathematics 2016-05-19 Wouter Cames van Batenburg , Ross J. Kang

For a fixed integer, the $k$-Colouring problem is to decide if the vertices of a graph can be coloured with at most $k$ colours for an integer $k$, such that no two adjacent vertices are coloured alike. A graph $G$ is $H$-free if $G$ does…

Combinatorics · Mathematics 2021-11-24 Barnaby Martin , Daniel Paulusma , Siani Smith

A graph is perfectly divisible if for each of its induced subgraph $H$, $V(H)$ can be partitioned into $A$ and $B$ such that $H[A]$ is perfect and $\omega(H[B]) < \omega(H)$, and a graph $G$ is perfectly weight divisible if for every…

Combinatorics · Mathematics 2026-03-06 Qiming Hu , Baogang Xu , Miaoxia Zhuang

Let v(G) be the number of vertices and t(G,k) the maximum number of disjoint k-edge trees in G. In this paper we show that (a1) if G is a graph with every vertex of degree at least two and at most s, where s > 3, then t(G,2) is at least…

Combinatorics · Mathematics 2007-05-23 Alexander Kelmans

Let G be a bridgeless cubic graph. A well-known conjecture of Berge and Fulkerson can be stated as follows: there exist five perfect matchings of G such that each edge of G is contained in at least one of them. Here, we prove that in each…

Combinatorics · Mathematics 2013-06-06 Giuseppe Mazzuoccolo

The $k$-Colouring problem is to decide if the vertices of a graph can be coloured with at most $k$ colours for a fixed integer $k$ such that no two adjacent vertices are coloured alike. If each vertex u must be assigned a colour from a…

Data Structures and Algorithms · Computer Science 2026-02-19 Tereza Klimošová , Josef Malík , Tomáš Masařík , Jana Novotná , Daniël Paulusma , Veronika Slívová

A complete graph is the graph in which every two vertices are adjacent. For a graph $G=(V,E)$, the complete width of $G$ is the minimum $k$ such that there exist $k$ independent sets $\mathtt{N}_i\subseteq V$, $1\le i\le k$, such that the…

Discrete Mathematics · Computer Science 2016-12-28 Van Bang Le , Sheng-Lung Peng

A graph H is strongly immersed in G if G is obtained from H by a sequence of vertex splittings (i.e., lifting some pairs of incident edges and removing the vertex) and edge removals. Equivalently, vertices of H are mapped to distinct…

Combinatorics · Mathematics 2013-04-03 Zdenek Dvorak , Tereza Klimosova

Given $D$ and $\gamma>0$, whenever $c>0$ is sufficiently small and $n$ sufficiently large, if $\mathcal{G}$ is a family of $D$-degenerate graphs of individual orders at most $n$, maximum degrees at most $\tfrac{cn}{\log n}$, and total…

Combinatorics · Mathematics 2022-04-19 Peter Allen , Julia Böttcher , Jan Hladký , Diana Piguet

We develop a method to study sufficient conditions for perfect mixed tilings. Our framework allows the embedding of bounded degree graphs $H$ with components of sublinear order. As a corollary, we recover and extend the work of K\"uhn and…

Combinatorics · Mathematics 2024-10-24 Eoin Hurley , Felix Joos , Richard Lang

A graph $G$ is $\textit{universal}$ for a (finite) family $\mathcal{H}$ of graphs if every $H \in \mathcal{H}$ is a subgraph of $G$. For a given family $\mathcal{H}$, the goal is to determine the smallest number of edges an…

Combinatorics · Mathematics 2024-01-12 Noga Alon , Natalie Dodson , Carmen Jackson , Rose McCarty , Rajko Nenadov , Lani Southern

Let $H=(V,E)$ be a hypergraph, where $V$ is a set of vertices and $E$ is a set of non-empty subsets of $V$ called edges. If all edges of $H$ have the same cardinality $r$, then $H$ is a $r$-uniform hypergraph; if $E$ consists of all…

Combinatorics · Mathematics 2018-08-03 Yingzhi Tian , Hong-Jian Lai , Jixiang Meng
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