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Related papers: Short proof of the hypergraph container theorem

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Konig's theorem states that the covering number and the matching number of a bipartite graph are equal. We prove a generalisation of this result, in which each point in one side of the graph is replaced by a subtree of a given tree. The…

Combinatorics · Mathematics 2007-05-23 Ron Aharoni , Eli Berger , Ran Ziv

Consider a host hypergraph $G$ which contains a spanning structure due to minimum degree considerations. We collect three results proving that if the edges of $G$ are sampled at the appropriate rate then the spanning structure still appears…

Combinatorics · Mathematics 2023-05-17 Huy Tuan Pham , Ashwin Sah , Mehtaab Sawhney , Michael Simkin

Let H be a k-uniform hypergraph whose vertices are the integers 1,...,N. We say that H contains a monotone path of length n if there are x_1 < x_2 < ... < x_{n+k-1} so that H contains all n edges of the form {x_i,x_{i+1},...,x_{i+k-1}}. Let…

Combinatorics · Mathematics 2012-06-19 Guy Moshkovitz , Asaf Shapira

In 1991, it was shown by Favaron, Mah\'eo, and Sacl\'e that the residue, which is defined as the number of zeros remaining when the Havel-Hakimi algorithm is applied to a degree sequence, yields a lower bound on the independence number of…

Combinatorics · Mathematics 2022-06-14 Michaela Hiller

Seymour conjectured that every oriented simple graph contains a vertex whose second neighborhood is at least as large as its first. Seymour's conjecture has been verified in several special cases, most notably for tournaments by Fisher. One…

Combinatorics · Mathematics 2012-12-11 Tyler Seacrest

Codes on hypergraphs are an extension of the well-studied family of codes on bipartite graphs. Bilu and Hoory (2004) constructed an explicit family of codes on regular t-partite hypergraphs whose minimum distance improves earlier estimates…

Information Theory · Computer Science 2008-12-10 Alexander Barg , Arya Mazumdar , Gilles Zémor

We establish a compensated compactness theorem in the microlocal and geometric analytic framework. For a weakly $L^2_{\rm loc}$-convergent sequence of sections of a vector bundle over a semi-Riemannian manifold whose image under a…

Functional Analysis · Mathematics 2026-03-03 Siran Li , Xiangxiang Su , Yuantu Zhu

Leighton's graph covering theorem says that two finite graphs with a common cover have a common finite cover. We present a new proof of this using groupoids, and use this as a model to prove two generalisations of the theorem. The first…

Group Theory · Mathematics 2022-08-25 Sam Shepherd , Giles Gardam , Daniel J. Woodhouse

We give a simple and natural (probabilistic) construction of hypergraph regularization. It is done just by taking a constant-bounded number of random vertex samplings only one time (thus, iteration-free). It is independent from the…

Combinatorics · Mathematics 2009-04-30 Yoshiyasu Ishigami

This is a companion paper to the paper "Hyperstability in the Erdos-Sos Conjecture". In that paper the following rough structure theorem was proved for graphs G containing no copy of a bounded degree tree T: from any such G, one can delete…

Combinatorics · Mathematics 2024-09-24 Alexey Pokrovskiy

A theorem is proved to verify incremental stability of a feedback system via a homotopy from a known incrementally stable system. A first corollary of that result is that incremental stability may be verified by separation of Scaled…

Optimization and Control · Mathematics 2024-12-03 Thomas Chaffey , Andrey Kharitenko , Fulvio Forni , Rodolphe Sepulchre

The Erd\H{o}s-Simonovits stability theorem is one of the most widely used theorems in extremal graph theory. We obtain an Erd\H{o}s-Simonovits type stability theorem in multi-partite graphs. Different from the Erd\H{o}s-Simonovits stability…

Combinatorics · Mathematics 2026-01-14 Wanfang Chen , Changhong Lu , Long-Tu Yuan

The goal of this notice is to present a proof of Bachet's conjecture based exclusively on the fundamental theorem of arithmetic. The novelty of this proof consists in its introduction of a partial order on rational integers through the…

Number Theory · Mathematics 2013-10-22 Felix Sidokhine

Given a family $\mathcal{H}$ of graphs, we say that a graph $G$ is $\mathcal{H}$-free if no induced subgraph of $G$ is isomorphic to a member of $\mathcal{H}$. Let $S_{t,t,t}$ be the graph obtained from $K_{1,3}$ by subdividing each edge…

Combinatorics · Mathematics 2025-02-10 Maria Chudnovsky , Julien Codsi , Daniel Lokshtanov , Martin Milanič , Varun Sivashankar

Classes of graphs with bounded expansion are a generalization of both proper minor closed classes and degree bounded classes. Such classes are based on a new invariant, the greatest reduced average density (grad) of G with rank r,…

Combinatorics · Mathematics 2007-05-23 Jaroslav Nesetril , Patrice Ossona De Mendez

We prove a general lemma about partitioning the vertex set of a graph into subgraphs of bounded degree. This lemma extends a sequence of results of Lov\'asz, Catlin, Kostochka and Rabern.

Combinatorics · Mathematics 2011-07-12 Landon Rabern

Robertson and Seymour proved that the relation of graph immersion is well-quasi-ordered for finite graphs. Their proof uses the results of graph minors theory. Surprisingly, there is a very short proof of the corresponding rough structure…

Combinatorics · Mathematics 2012-07-10 Matt DeVos , Jessica McDonald , Bojan Mohar , Diego Scheide

The graph reconstruction conjecture asserts that every simple graph on at least three vertices is uniquely determined by its deck of vertex-deleted subgraphs. In this expository article we survey the conjecture and present an…

Combinatorics · Mathematics 2026-04-21 Emilie Dufresne , Gabriela Jeronimo , Jenny Kenkel , Haydee Lindo , Nelly Villamizar

A loose Hamilton cycle in a hypergraph is a cyclic sequence of edges covering all vertices in which only every two consecutive edges intersect and do so in exactly one vertex. With Dirac's theorem in mind, it is natural to ask what minimum…

Combinatorics · Mathematics 2024-04-29 Kalina Petrova , Miloš Trujić

Let $G$ be an $n$-vertex graph, and $s,t$ vertices of $G$. We present an efficient algorithm which enumerates the set of minimal $st$-separators of $G$ in ascending order of cardinality, with a delay of $O(n^{3.5})$ per separator. In…

Data Structures and Algorithms · Computer Science 2021-12-03 Batya Kenig