English
Related papers

Related papers: Spanning spheres in Dirac hypergraphs

200 papers

We prove a topological extension of Dirac's theorem suggested by Gowers in 2005: for any connected, closed surface $\mathscr{S}$, we show that any two-dimensional simplicial complex on $n$ vertices in which each pair of vertices belongs to…

Combinatorics · Mathematics 2022-06-14 Agelos Georgakopoulos , John Haslegrave , Richard Montgomery , Bhargav Narayanan

We prove that for fixed $k$, every $k$-uniform hypergraph on $n$ vertices and of minimum codegree at least $n/2+o(n)$ contains every spanning tight $k$-tree of bounded vertex degree as a sub\-graph. This generalises a well-known result of…

Combinatorics · Mathematics 2023-06-12 Matías Pavez-Signé , Nicolás Sanhueza-Matamala , Maya Stein

For positive integers $d<k$ and $n$ divisible by $k$, let $m_{d}(k,n)$ be the minimum $d$-degree ensuring the existence of a perfect matching in a $k$-uniform hypergraph. In the graph case (where $k=2$), a classical theorem of Dirac says…

Combinatorics · Mathematics 2022-08-05 Asaf Ferber , Matthew Kwan

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

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

A famous result by R\"odl, Ruci\'nski, and Szemer\'edi guarantees a (tight) Hamilton cycle in $k$-uniform hypergraphs $H$ on $n$ vertices with minimum $(k-1)$-degree $\delta_{k-1}(H)\geq (1/2+o(1))n$, thereby extending Dirac's result from…

Combinatorics · Mathematics 2021-04-14 Felix Joos , Marcus Kühn , Bjarne Schülke

We prove that for every integer $r\geq 2$, an $n$-vertex $k$-uniform hypergraph $H$ containing no $r$-regular subgraphs has at most $(1+o(1)){{n-1}\choose{k-1}}$ edges if $k\geq r+1$ and $n$ is sufficiently large. Moreover, if…

Combinatorics · Mathematics 2016-04-26 Jaehoon Kim

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

A Hamilton Berge cycle of a hypergraph on $n$ vertices is an alternating sequence $(v_1, e_1, v_2, \ldots, v_n, e_n)$ of distinct vertices $v_1, \ldots, v_n$ and distinct hyperedges $e_1, \ldots, e_n$ such that $\{v_1,v_n\}\subseteq e_n$…

Combinatorics · Mathematics 2019-03-22 Dennis Clemens , Julia Ehrenmüller , Yury Person

We say that a k-uniform hypergraph C is an l-cycle if there exists a cyclic ordering of the vertices of C such that every edge of C consists of k consecutive vertices and such that every pair of consecutive edges (in the natural ordering of…

Combinatorics · Mathematics 2013-08-15 Daniela Kühn , Richard Mycroft , Deryk Osthus

Let $n$ and $r$ be integers with $n-2\ge r\ge 3$. We prove that any $r$-uniform hypergraph $\mathcal{H}$ on $n$ vertices with spectral radius $\lambda(\mathcal{H}) > \binom{n-2}{r-1}$ must contain a Hamiltonian Berge cycle unless…

Combinatorics · Mathematics 2026-04-14 George Brooks , William Linz , Ruth Luo

We show that every graph $G$ on $n$ vertices with $\delta(G) \geq (1/2+\varepsilon)n$ is spanned by a complete blow-up of a cycle with clusters of nearly uniform size $\Omega(\log n)$. The proof is based on a recently introduced approach…

Combinatorics · Mathematics 2025-12-16 Richard Lang , Nicolás Sanhueza-Matamala

The (k,d)-hypersimplex is a (d-1)-dimensional polytope whose vertices are the (0,1)-vectors that sum to k. When k=1, we get a simplex whose graph is the complete graph with d vertices. Here we show how many of the well known graph…

Combinatorics · Mathematics 2008-11-19 Fred J. Rispoli

We give several results showing that different discrete structures typically gain certain spanning substructures (in particular, Hamilton cycles) after a modest random perturbation. First, we prove that adding linearly many random edges to…

Combinatorics · Mathematics 2018-03-23 Michael Krivelevich , Matthew Kwan , Benny Sudakov

For $\ell \geq 3$, an $\ell$-uniform hypergraph is disperse if the number of edges induced by any set of $\ell+1$ vertices is 0, 1, $\ell$ or $\ell+1$. We show that every disperse $\ell$-uniform hypergraph on $n$ vertices contains a clique…

Combinatorics · Mathematics 2025-08-26 Lior Gishboliner , Ethan Honest

A fundamental question in graph theory is to establish conditions that ensure a graph contains certain spanning subgraphs. Two well-known examples are Tutte's theorem on perfect matchings and Dirac's theorem on Hamilton cycles.…

Combinatorics · Mathematics 2015-08-26 Yi Zhao

We show that $k$-uniform hypergraphs on $n$ vertices whose codegree is at least $(2/3 + o(1))n$ can be decomposed into tight cycles, subject to the trivial divisibility conditions. As a corollary, we show those graphs contain tight Euler…

Combinatorics · Mathematics 2024-03-07 Allan Lo , Simón Piga , Nicolás Sanhueza-Matamala

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

A meta-conjecture of Coulson, Keevash, Perarnau and Yepremyan states that above the extremal threshold for a given spanning structure in a (hyper-)graph, one can find a rainbow version of that spanning structure in any suitably bounded…

Combinatorics · Mathematics 2026-02-25 Amarja Kathapurkar , Patrick Morris , Guillem Perarnau

This paper introduces a geometric representation of hypergraphs by representing hyperedges as simplices. Building on this framework, we employ homotopy groups to analyze the topological structure of hypergraphs embedded in high-dimensional…

Combinatorics · Mathematics 2025-11-14 Qiming Fang , Sihong Shao
‹ Prev 1 2 3 10 Next ›