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Let $A_{s,k}(m)$ be the maximum number of distinct letters in any sequence which can be partitioned into $m$ contiguous blocks of pairwise distinct letters, has at least $k$ occurrences of every letter, and has no subsequence forming an…

Combinatorics · Mathematics 2014-09-23 Jesse Geneson

We study packing densities for set partitions, which is a generalization of packing words. We use results from the literature about packing densities for permutations and words to provide packing densities for set partitions. These results…

Combinatorics · Mathematics 2015-04-10 Adam M. Goyt , Lara K. Pudwell

We show that, there exists a constant $a$ such that, for every subgroup $H$ of a finite group $G$, the number of maximal subgroups of $G$ containing $H$ is bounded above by $a|G:H|^{3/2}$. In particular, a transitive permutation group of…

Group Theory · Mathematics 2019-07-22 Andrea Lucchini , Mariapia Moscatiello , Pablo Spiga

Let $\mathbb{Z}_n$ denote the ring of integers modulo $n$. In this paper we consider two extremal problems on permutations of $\mathbb{Z}_n$, namely, the maximum size of a collection of permutations such that the sum of any two distinct…

Combinatorics · Mathematics 2014-02-18 L. Sunil Chandran , Deepak Rajendraprasad , Nitin Singh

Inspired by the results of Baik, Deift and Johansson on the limiting distribution of the lengths of the longest increasing subsequences in random permutations, we find those limiting distributions for pattern-restricted permutations in…

Combinatorics · Mathematics 2009-09-29 Emeric Deutsch , A. J. Hildebrand , Herbert S. Wilf

We consider the cycle structure of a random permutation $\sigma$ chosen uniformly from the symmetric group, subject to the constraint that $\sigma$ does not contain cycles of length exceeding $r.$ We prove that under suitable conditions the…

Probability · Mathematics 2019-05-14 David Judkovich

We show, by an explicit construction, that a mixture of univariate Gaussian densities with variance $1$ and means in $[-A,A]$ can have $\Omega(A^2)$ modes. This disproves a recent conjecture of Dytso, Yagli, Poor and Shamai \cite{DYPS20}…

Statistics Theory · Mathematics 2020-10-23 Navin Kashyap , Manjunath Krishnapur

Let $S_n$ be the set of all permutations of $\{1,2,\ldots,n\}$ and let $\sigma=(\sigma_1,\sigma_2,\ldots,\sigma_n)\in S_n$. The {\it initial longest increasing sequence} (ILIS) in $\sigma$ has length $m$ if, for $1\le m\le n-1$,…

Combinatorics · Mathematics 2025-10-01 Ljuben Mutafchiev

Let $S^B_n$ be the Coxeter group of type B. We denote the set of indices where $\sigma\in S^B_n$ has a peak as $Peak(\sigma)$ and let $P^{B}(S;n)=\{\sigma \in S^{B}_n~|~ Peak(\sigma)=S\}$. In \cite{metrics}, Diaz-Lopez, Haymaker, Keough,…

Consider a permutation $\sigma\in S_n$ as a deck of cards numbered from 1 to $n$ and laid out in a row, where $\sigma_j$ denotes the number of the card that is in the $j$-th position from the left.\rm\ We define two cyclic to random…

Probability · Mathematics 2012-04-11 Ross G. Pinsky

In this paper, we connect two types of representations of a permutation $\sigma$ of the finite field $\F_q$. One type is algebraic, in which the permutation is represented as the composition of degree-one polynomials and $k$ copies of…

Number Theory · Mathematics 2021-03-17 Zhiguo Ding

Let $S_n$ be the symmetric group on the set $[n]:=\{1,2,\ldots,n\}$. Given a permutation $\sigma=\sigma_1\sigma_2 \cdots \sigma_n \in S_n$, we say it has a descent at index $i$ if $\sigma_i>\sigma_{i+1}$. Let $\mathcal{D}(\sigma)$ be the…

Combinatorics · Mathematics 2024-05-13 Alexander Diaz-Lopez , Kathryn Haymaker , Colin McGarry , Dylan McMahon

In the course of classifying the homogeneous permutations, Cameron introduced the viewpoint of permutations as structures in a language of two linear orders, and this structural viewpoint is taken up here. The majority of this thesis is…

Logic · Mathematics 2018-05-14 Samuel Braunfeld

A permutation p is realized by the shift on N symbols if there is an infinite word on an N-letter alphabet whose successive left shifts by one position are lexicographically in the same relative order as p. The set of realized permutations…

Combinatorics · Mathematics 2009-09-15 Sergi Elizalde

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…

A matrix group is said to be permutation-like if any matrix of the group is similar to a permutation matrix. G. Cigler proved that, if a permutation-like matrix group contains a normal cyclic subgroup which is generated by a maximal cycle…

Group Theory · Mathematics 2013-11-27 Guodong Deng , Yun Fan

We prove that for all fixed $p > 2$, the translative packing density of unit $\ell_p$-balls in $\mathbb{R}^n$ is at most $2^{(\gamma_p + o(1))n}$ with $\gamma_p < - 1/p$. This is the first exponential improvement in high dimensions since…

Metric Geometry · Mathematics 2020-02-17 Ashwin Sah , Mehtaab Sawhney , David Stoner , Yufei Zhao

Let $S_{\rm div}(n)$ denote the set of permutations $\pi$ of $n$ such that for each $1\leq j \leq n$ either $j \mid \pi(j)$ or $\pi(j) \mid j$. These permutations can also be viewed as vertex-disjoint directed cycle covers of the divisor…

Number Theory · Mathematics 2022-09-29 Nathan McNew

Let $0\le \alpha \le \beta\le 1$. For any finite set $B\subset\mathbb{N}$, we show that there exists a set $A\subset\mathbb{N}$ such that $\underline{d}(A+B) = \alpha$ and $\bar{d}(A+B) = \beta$, where $\underline{d}(A+ B)$ and…

Combinatorics · Mathematics 2022-07-05 Hung Viet Chu

For distinct unitary cuspidal automorphic representations $\pi_1$ and $\pi_2$ for $\mathrm{GL}(2)$ over a number field $F$ and any $\alpha\in\Bbb{R}$, let $\mathcal{S}_{\alpha}$ be the set of primes $v$ of $F$ for which…

Number Theory · Mathematics 2022-03-22 Peng-Jie Wong
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