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Related papers: Blowing up Dirac's theorem

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Dirac's theorem states that any $n$-vertex graph $G$ with even integer $n$ satisfying $\delta(G) \geq n/2$ contains a perfect matching. We generalize this to $k$-uniform linear hypergraphs by proving the following. Any $n$-vertex…

Combinatorics · Mathematics 2025-03-27 Seonghyuk Im , Hyunwoo Lee

A cornerstone of extremal graph theory due to Erd\H{o}s and Stone states that the edge density which guarantees a fixed graph $F$ as subgraph also asymptotically guarantees a blow-up of $F$ as subgraph. It is natural to ask whether this…

Combinatorics · Mathematics 2026-04-01 Richard Lang , Nicolás Sanhueza-Matamala

The classical Dirac theorem asserts that every graph $G$ on $n$ vertices with minimum degree $\delta(G) \ge \lceil n/2 \rceil$ is Hamiltonian. The lower bound of $\lceil n/2 \rceil$ on the minimum degree of a graph is tight. In this paper,…

Discrete Mathematics · Computer Science 2016-06-14 Yasemin Büyükçolak , Didem Gözüpek , Sibel Özkan , Mordechai Shalom

Let $G$ be an $n$-vertex graph with $n\ge 3$. A classic result of Dirac from 1952 asserts that $G$ is hamiltonian if $\delta(G)\ge n/2$. Dirac's theorem is one of the most influential results in the study of hamiltonicity and by now there…

Combinatorics · Mathematics 2017-07-18 Guantao Chen , Songling Shan

The problem of packing Hamilton cycles in random and pseudorandom graphs has been studied extensively. In this paper, we look at the dual question of covering all edges of a graph by Hamilton cycles and prove that if a graph with maximum…

Combinatorics · Mathematics 2011-11-15 Roman Glebov , Michael Krivelevich , Tibor Szabó

Dirac's classical theorem asserts that, for $n \ge 3$, any $n$-vertex graph with minimum degree at least $n/2$ is Hamiltonian. Furthermore, if we additionally assume that such graphs are regular, then, by the breakthrough work of Csaba,…

The famous Dirac's Theorem gives an exact bound on the minimum degree of an $n$-vertex graph guaranteeing the existence of a hamiltonian cycle. We prove exact bounds of similar type for hamiltonian Berge cycles in $r$-uniform, $n$-vertex…

Combinatorics · Mathematics 2022-11-08 Alexandr Kostochka , Ruth Luo , Grace McCourt

We show that for every $n\in\mathbb N$ and $\log n\le d\le n$, if a graph $G$ has $N=\Theta(dn)$ vertices and minimum degree $(1+o(1))\frac{N}{2}$, then it contains a spanning subdivision of every $n$-vertex $d$-regular graph.

Combinatorics · Mathematics 2023-09-13 Matías Pavez-Signé

The blow-up lemma states that a system of super-regular pairs contains all bounded degree spanning graphs as subgraphs that embed into a corresponding system of complete pairs. This lemma has far-reaching applications in extremal…

Combinatorics · Mathematics 2025-08-29 Peter Allen , Julia Böttcher , Hiep Hàn , Yoshiharu Kohayakawa , Yury Person

Dirac proved that each $n$-vertex $2$-connected graph with minimum degree at least $k$ contains a cycle of length at least $\min\{2k, n\}$. We consider a hypergraph version of this result. A Berge cycle in a hypergraph is an alternating…

Combinatorics · Mathematics 2024-03-01 Alexandr Kostochka , Ruth Luo , Grace McCourt

In a recent work, Allen, B\"{o}ttcher, H\`{a}n, Kohayakawa, and Person provided a first general analogue of the blow-up lemma applicable to sparse (pseudo)random graphs thus generalising the classic tool of Koml\'{o}s, S\'{a}rk\"{o}zy, and…

Combinatorics · Mathematics 2021-11-18 Miloš Trujić

A graph is Hamiltonian if it contains a cycle which passes through every vertex of the graph exactly once. A classical theorem of Dirac from 1952 asserts that every graph on $n$ vertices with minimum degree at least $n/2$ is Hamiltonian. We…

Combinatorics · Mathematics 2012-09-24 Michael Krivelevich , Choongbum Lee , Benny Sudakov

We show that for each \alpha>0 every sufficiently large oriented graph G with \delta^+(G),\delta^-(G)\ge 3|G|/8+ \alpha |G| contains a Hamilton cycle. This gives an approximate solution to a problem of Thomassen. In fact, we prove the…

Combinatorics · Mathematics 2009-09-29 Luke Kelly , Daniela Kühn , Deryk Osthus

We show that if a graph G of order n contains many copies of a given subgraph H, then it contains a blow-up of H of order log n.

Combinatorics · Mathematics 2007-11-26 Vladimir Nikiforov

In 1952, Dirac proved the following theorem about long cycles in graphs with large minimum vertex degrees: Every $n$-vertex $2$-connected graph $G$ with minimum vertex degree $\delta\geq 2$ contains a cycle with at least $\min\{2\delta,n\}$…

Data Structures and Algorithms · Computer Science 2024-04-15 Fedor V. Fomin , Petr A. Golovach , Danil Sagunov , Kirill Simonov

We show that a $k$-uniform hypergraph on $n$ vertices has a spanning subgraph homeomorphic to the $(k - 1)$-dimensional sphere provided that $H$ has no isolated vertices and each set of $k - 1$ vertices supported by an edge is contained in…

Combinatorics · Mathematics 2025-06-17 Freddie Illingworth , Richard Lang , Alp Müyesser , Olaf Parczyk , Amedeo Sgueglia

An influential theorem of Nikiforov states that if an $N$-vertex graph $G$ contains at least $\gamma N^h$ copies of some fixed $h$-vertex graph $H$, then $G$ contains an $H$-blowup of order $c_H(\gamma)\log N$. We provide a new proof of…

Combinatorics · Mathematics 2026-05-25 Jacob Fox , Yuval Wigderson , Yunkun Zhou

The blow-up of a graph is obtained by replacing every vertex with a finite collection of copies so that the copies of two vertices are adjacent if and only if the originals are. If every vertex is replaced with the same number of copies,…

Combinatorics · Mathematics 2011-08-30 Hamed Hatami , James Hirst , Serguei Norine

Let $G$ be a graph on an even number $n$ of vertices and let ${\cal M}_G$ be the collection of perfect matchings in $G$. Dirac's theorem says that if the minimum degree $\delta(G)$ of $G$ is at least $n/2$, then ${\cal M}_G$ is guaranteed…

Combinatorics · Mathematics 2026-04-21 Ross J. Kang , Clément Legrand-Duchesne

Let $G$ be an edge-coloured graph. The minimum colour degree $ \delta^c(G) $ of $G$ is the largest integer $k$ such that, for every vertex $v$, there are at least $k$ distinct colours on edges incident to $v$. We say that $G$ is properly…

Combinatorics · Mathematics 2013-12-11 Allan Lo
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