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A numerical semigroup is a subset of the non-negative integers that is closed under addition. For a randomly generated numerical semigroup, the expected number of minimum generators can be expressed in terms of a doubly-indexed sequence of…

Combinatorics · Mathematics 2018-09-27 Calvin Leng , Christopher O'Neill

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

An $n$-vertex graph $G$ of edge density $p$ is considered to be quasirandom if it shares several important properties with the random graph $G(n,p)$. A well-known theorem of Chung, Graham and Wilson states that many such `typical'…

Combinatorics · Mathematics 2020-06-17 E. Aigner-Horev , D. Conlon , H. Hàn , Y. Person , M. Schacht

It is shown that a natural notion of congruence permutability for quasivarieties already implies ``being a variety''. The result follows immediately from [3] and the sole aim of this note is to state it explicitly, together with a…

Logic · Mathematics 2025-12-11 Luca Carai , Miriam Kurtzhals , Tommaso Moraschini

Previously, the author introduced quasirandom permutations, permutations of $\mathbb{Z}_n$ which map intervals to sets with low discrepancy. Here we show that several natural number-theoretic permutations are quasirandom, some very strongly…

Number Theory · Mathematics 2007-05-23 Joshua N. Cooper

We isolate a new class of ultrafilters on N, called "quasi-selective" because they are intermediate between selective ultrafilters and P-points. (Under the Continuum Hypothesis these three classes are distinct.) The existence of…

Logic · Mathematics 2017-12-19 Andreas Blass , Mauro Di Nasso , Marco Forti

We prove a conjecture by Garbe et al. [arXiv:2010.07854] by showing that a Latin square is quasirandom if and only if the density of every 2x3 pattern is 1/720+o(1). This result is the best possible in the sense that 2x3 cannot be replaced…

Combinatorics · Mathematics 2021-08-27 Jacob W. Cooper , Daniel Kral , Ander Lamaison , Samuel Mohr

We establish a new mixing theorem for quasirandom groups (finite groups with no low-dimensional unitary representations) $G$ which, informally speaking, asserts that if $g, x$ are drawn uniformly at random from $G$, then the quadruple…

Dynamical Systems · Mathematics 2013-08-05 Vitaly Bergelson , Terence Tao

One of the main questions that arise when studying random and quasi-random structures is which properties P are such that any object that satisfies P "behaves" like a truly random one. In the context of graphs, Chung, Graham, and Wilson…

Combinatorics · Mathematics 2009-03-03 Asaf Shapira , Raphael Yuster

For some m \ge 4, let us color each column of the integer lattice L = Z^2 independently and uniformly into one of m colors. We do the same for the rows, independently from the columns. A point of L will be called blocked if its row and…

Probability · Mathematics 2007-05-23 Peter Gacs

A Boolean function is symmetric if it is invariant under all permutations of its arguments; it is quasi-symmetric if it is symmetric with respect to the arguments on which it actually depends. We present a test that accepts every…

Computational Complexity · Computer Science 2007-08-17 Krzysztof Majewski , Nicholas Pippenger

We study some properties of graphs (or, rather, graph sequences) defined by demanding that the number of subgraphs of a given type, with vertices in subsets of given sizes, approximatively equals the number expected in a random graph. It…

Combinatorics · Mathematics 2014-05-28 Svante Janson , Vera T. Sós

We show that a number of conditions on oriented graphs, all of which are satisfied with high probability by randomly oriented graphs, are equivalent. These equivalences are similar to those given by Chung, Graham and Wilson in the case of…

Combinatorics · Mathematics 2011-08-12 Simon Griffiths

We explore how the asymptotic structure of a random permutation of $[n]$ with $m$ inversions evolves, as $m$ increases, establishing thresholds for the appearance and disappearance of any classical, consecutive or vincular pattern. The…

Combinatorics · Mathematics 2024-08-13 David Bevan , Dan Threlfall

A permutation sequence is said to be convergent if the density of occurrences of every fixed permutation in the elements of the sequence converges. We prove that such a convergent sequence has a natural limit object, namely a Lebesgue…

Every set $\Lambda\subset R$ such that the sum of $\delta$-measures sitting at the points of $\Lambda$ is a Fourier quasicrystal, is the zero set of an exponential polynomial with imaginary frequencies.

Classical Analysis and ODEs · Mathematics 2020-09-29 Alexander Olevskii , Alexander Ulanovskii

Recently P. Wocjan and M. Horodecki [quant-ph/0503129] gave a characterization of combinatorially independent permutation separability criteria. Combinatorial independence is a necessary condition for permutations to yield truly independent…

Quantum Physics · Physics 2007-05-23 Lieven Clarisse , Pawel Wocjan

The goal of property testing is to quickly distinguish between objects which satisfy a property and objects that are $\epsilon$-far from satisfying the property. There are now several general results in this area which show that natural…

Combinatorics · Mathematics 2018-04-05 Jacob Fox , Fan Wei

Fix $\varepsilon > 0$. We say that a finite group $G$ is $\varepsilon$-quasirandom if every nontrivial irreducible complex representation of $G$ has degree at least $|G|^\varepsilon$. In this paper, we give a structure theorem for large…

Group Theory · Mathematics 2025-10-02 Marco Barbieri , Luca Sabatini

In this paper we give a bijection between the class of permutations that can be drawn on an X-shape and a certain set of permutations that appears in [Knuth] in connection to sorting algorithms. A natural generalization of this set leads us…

Combinatorics · Mathematics 2007-10-29 Sergi Elizalde