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Related papers: Irregular triads in 3-uniform hypergraphs

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The uniform Tur\'an density $\pi_{u}(F)$ of a $3$-uniform hypergraph (or $3$-graph) $F$ is the supremum of all $d$ such that there exist infinitely many $F$-free $3$-graphs $H$ in which every induced subhypergraph on a linearly sized vertex…

Combinatorics · Mathematics 2026-03-12 Hao Lin , Guanghui Wang , Wenling Zhou , Yiming Zhou

In this work, some combinatorial lower bound for regularity of powers of the edge ideal of a uniform hypergarph is gained. A family of hypergraphs whose regularity of edge ideal attains this bound and has a significant difference from the…

Commutative Algebra · Mathematics 2025-06-03 Fahimeh Khosh-Ahang Ghasr

We provide a combinatorial characterization of all testable properties of $k$-uniform hypergraphs ($k$-graphs for short). Here, a $k$-graph property $P$ is testable if there is a randomized algorithm which makes a bounded number of edge…

Combinatorics · Mathematics 2025-05-08 Felix Joos , Jaehoon Kim , Daniela Kühn , Deryk Osthus

In this article, we give a new upper bound for the regularity of edge ideals of gap-free graphs, in terms of the their minimal triangulation. Let $H_U=G\cup F_U$ be a minimal triangulation of a gap-free graph $G$, for some maximal…

Combinatorics · Mathematics 2021-09-13 Rimpa Nandi , Ramakrishna Nanduri

We prove algorithmic weak and \Szemeredi{} regularity lemmas for several classes of sparse graphs in the literature, for which only weak regularity lemmas were previously known. These include core-dense graphs, low threshold rank graphs,…

Data Structures and Algorithms · Computer Science 2025-05-30 Greg Bodwin , Santosh Vempala

Hyperuniformity is a property of certain heteroneous media in which density fluctuations in the long wavelength range decay to zero. In reciprocal space this behavior translates into a decay of Fourier intensities in the range near small…

Applied Physics · Physics 2023-09-08 Mario Lázaro , Luis M. García-Raffi

We present a systematic study of the regularity phenomena for NIP hypergraphs and connections to the theory of (locally) generically stable measures, providing a model-theoretic hypergraph version of the results from [L. Lov\'asz, B.…

Logic · Mathematics 2021-03-11 Artem Chernikov , Sergei Starchenko

We investigate extremal problems for quasirandom hypergraphs. We say that a $3$-uniform hypergraph $H=(V,E)$ is $(d,\eta)$-quasirandom if for any subset $X\subseteq V$ and every set of pairs $P\subseteq V\times V$ the number of pairs…

Combinatorics · Mathematics 2016-09-20 Christian Reiher , Vojtěch Rödl , Mathias Schacht

The perfect matching polytope, i.e. the convex hull of (incidence vectors of) perfect matchings of a graph is used in many combinatorial algorithms. Kotzig, Lov\'asz and Plummer developed a decomposition theory for graphs with perfect…

Combinatorics · Mathematics 2019-03-01 Isabel Beckenbach , Meike Hatzel , Sebastian Wiederrecht

Partite, $3$-uniform hypergraphs are $3$-uniform hypergraphs in which each hyperedge contains exactly one point from each of the $3$ disjoint vertex classes. We consider the degree sequence problem of partite, $3$-uniform hypergraphs, that…

Combinatorics · Mathematics 2023-08-28 Andras Hubai , Tamas Robert Mezei , Ferenc Beres , Andras Benczur , Istvan Miklos

An ordered graph is a graph together with a linear order on its vertices. A hereditary property of ordered graphs is a collection of ordered graphs closed under taking induced ordered subgraphs. If P is a property of ordered graphs, then…

Combinatorics · Mathematics 2007-05-23 József Balogh , Béla Bollobás , Robert Morris

Hypergraphs are structures that can be decomposed or described; in other words they are recursively countable. Here, we get exact and asymptotic enumeration results on hypergraphs by means of exponential generating functions. The number of…

Discrete Mathematics · Computer Science 2008-06-20 Tsiriniaina Andriamampianina

We study the problems of bounding the number weak and strong independent sets in $r$-uniform, $d$-regular, $n$-vertex linear hypergraphs with no cross-edges. In the case of weak independent sets, we provide an upper bound that is tight up…

Combinatorics · Mathematics 2021-07-06 Emma Cohen , Will Perkins , Michail Sarantis , Prasad Tetali

We generalize the fact that graphs with small VC-dimension can be approximated by rectangles, showing that hypergraphs with small VC_k-dimension (equivalently, omitting a fixed finite (k+1)-partite (k+1)-uniform hypergraph) can be…

Combinatorics · Mathematics 2020-10-05 Artem Chernikov , Henry Towsner

An intuitive property of a random graph is that its subgraphs should also appear randomly distributed. We consider graphs whose subgraph densities exactly match their expected values. We call graphs with this property for all subgraphs with…

Combinatorics · Mathematics 2020-03-10 Sebastian Jeon , Tanya Khovanova

We investigate finite 3-nets embedded in a projective plane over a (finite or infinite) field of any characteristic p. Such an embedding is regular when each of the three classes of the 3-net comprises concurrent lines, and irregular…

Combinatorics · Mathematics 2009-11-23 Aart Blokhuis , Gábor Korchmáros , Francesco Mazzocca

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

In this paper we consider a natural extremal graph theoretic problem of topological sort, concerning the minimization of the (topological) connectedness of the independence complex of graphs in terms of its dimension. We observe that the…

Combinatorics · Mathematics 2016-06-21 Penny Haxell , Lothar Narins , Tibor Szabó

Hypergraph expanders are hypergraphs with surprising, non-intuitive expansion properties. In a recent paper, the first author gave a simple construction, which can be randomized, of $3$-uniform hypergraph expanders with polylogarithmic…

Combinatorics · Mathematics 2020-07-27 David Conlon , Jonathan Tidor , Yufei Zhao

A bipartite graph $H$ is said to have Sidorenko's property if the probability that the uniform random mapping from $V(H)$ to the vertex set of any graph $G$ is a homomorphism is at least the product over all edges in $H$ of the probability…

Combinatorics · Mathematics 2018-07-11 David Conlon , Jeong Han Kim , Choongbum Lee , Joonkyung Lee