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Related papers: Sigma-Algebras for Quasirandom Hypergraphs

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We consider sequences of graphs and define various notions of convergence related to these sequences: ``left convergence'' defined in terms of the densities of homomorphisms from small graphs into the graphs of the sequence, and ``right…

Combinatorics · Mathematics 2007-05-23 C. Borgs , J. T. Chayes , L. Lovasz , V. T. Sos , K. Vesztergombi

A finite group $G$ is called $C$-quasirandom (by Gowers) if all non-trivial irreducible complex representations of $G$ have dimension at least $C$. For any unit $\ell^{2}$ function on a finite group we associate the quantum probability…

Spectral Theory · Mathematics 2023-12-19 Michael Magee , Joe Thomas , Yufei Zhao

We study generalized quasirandom graphs whose vertex set consists of $q$ parts (of not necessarily the same sizes) with edges within each part and between each pair of parts distributed quasirandomly; such graphs correspond to the…

Combinatorics · Mathematics 2023-08-22 Andrzej Grzesik , Daniel Kral , Oleg Pikhurko

We construct explicit families of graphs whose eigenvalues are asymptotically distributed according to Wigner's semicircle law; in other words, that are spectrally indistinguishable from random graphs. However, in other respects they are…

Combinatorics · Mathematics 2025-11-27 Arthur Forey , Javier Fresán , Emmanuel Kowalski , Yuval Wigderson

Fox, Gromov, Lafforgue, Naor, and Pach proved a regularity lemma for semi-algebraic $k$-uniform hypergraphs of bounded complexity, showing that for each $\epsilon>0$ the vertex set can be equitably partitioned into a bounded number of parts…

Combinatorics · Mathematics 2016-10-17 Jacob Fox , Janos Pach , Andrew Suk

Inspired by results for graph $C^*$-algebras, we investigate connections between the ideal structure of an inverse semigroup $S$ and that of its tight $C^*$-algebra by relating ideals in $S$ to certain open invariant sets in the associated…

Operator Algebras · Mathematics 2019-01-29 Scott M. LaLonde , David Milan , Jamie Scott

We investigate the algebra of an ample groupoid, introduced by Steinberg, over a semifield S. In particular, we obtain a complete characterization of congruence-simpleness for Steinberg algebras of second-countable ample groupoids,…

Rings and Algebras · Mathematics 2021-09-10 Tran Giang Nam , Jens Zumbrägel

Subgraph densities have been defined, and served as basic tools, both in the case of graphons (limits of dense graph sequences) and graphings (limits of bounded-degree graph sequences). While limit objects have been described for the…

Combinatorics · Mathematics 2021-05-11 Dávid Kunszenti-Kovács , László Lovász , Balázs Szegedy

The celebrated theorem of Chung, Graham, and Wilson on quasirandom graphs implies that if the 4-cycle and edge counts in a graph $G$ are both close to their typical number in $\mathbb{G}(n,1/2),$ then this also holds for the counts of…

Statistics Theory · Mathematics 2025-04-25 Kiril Bangachev , Guy Bresler

A semigroupoid is a set equipped with a partially defined associative operation. Given a semigroupoid \Lambda we construct a C*-algebra C*(\Lambda) from it. We then present two main examples of semigroupoids, namely the Markov semigroupoid…

Operator Algebras · Mathematics 2007-05-23 Ruy Exel

We consider $K$-semialgebras for a commutative semiring $K$ that are at the same time $\Sigma$-algebras and satisfy certain linearity conditions. When each finite system of guarded polynomial fixed point equations has a unique solution over…

Discrete Mathematics · Computer Science 2015-03-19 Zoltan Esik

For a constant $\gamma \in[0,1]$ and a graph $G$, let $\omega_{\gamma}(G)$ be the largest integer $k$ for which there exists a $k$-vertex subgraph of $G$ with at least $\gamma\binom{k}{2}$ edges. We show that if $0<p<\gamma<1$ then…

Combinatorics · Mathematics 2018-03-29 Paul Balister , Béla Bollobás , Julian Sahasrabudhe , Alexander Veremyev

In this paper, we investigate the properties of $\sigma$-A-nuclei of a quasigroup including relations between them and relations between their respective component sets, where $\sigma \in S_3$. We also find connections between components of…

Group Theory · Mathematics 2022-05-03 Dimpy Chauhan , Indivar Gupta , Rashmi Verma

We appeal to results from combinatorial random matrix theory to deduce that various random graph $\mathrm{C}^*$-algebras are asymptotically almost surely Kirchberg algebras with trivial $K_1$. This in particular implies that, with high…

Operator Algebras · Mathematics 2025-05-22 Bhishan Jacelon , Igor Khavkine

We investigate the emergence of spanning structures in sparse pseudo-random $k$-uniform hypergraphs, using the following comparatively weak notion of pseudo-randomness. A $k$-uniform hypergraph $H$ on $n$ vertices is called…

Combinatorics · Mathematics 2021-08-11 Hiep Hàn , Jie Han , Patrick Morris

In this paper we describe a triple correspondence between graph limits, information theory and group theory. We put forward a new graph limit concept called log-convergence that is closely connected to dense graph limits but its main…

Combinatorics · Mathematics 2015-04-06 Balazs Szegedy

We introduce and study a new class of topological $G$-spaces generalizing the classical flag manifolds $G/T$ of compact connected Lie groups. These spaces, which we call the $m$-quasi-flag manifolds $ F_m = F_m(G,T) $, are topological…

Algebraic Topology · Mathematics 2025-10-06 Yuri Berest , Yun Liu , Ajay C. Ramadoss

We use the theory of graph limits to study several quasi-random properties, mainly dealing with various versions of hereditary subgraph counts. The main idea is to transfer the properties of (sequences of) graphs to properties of graphons,…

Combinatorics · Mathematics 2009-05-21 Svante Janson

We define a notion of quantum automorphism group of Graph C*-algebras for finite, connected graphs. Under the assumption that the underlying graph does not have any multiple edge or loop, the quantum automorphism group of underlying…

Operator Algebras · Mathematics 2018-10-11 Soumalya Joardar , Arnab Mandal

In this paper we characterize left(right) ideals, bi-ideals and quasi-ideals of an ordered semigroup by an index $m$ and give some important interplays between these ideals. The concept of m-regularity of an ordered semigroups has been…

Group Theory · Mathematics 2022-03-22 Susmita Mallick