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Bukh and Zhou conjectured that the expectation of the length of the longest common subsequence of two i.i.d random permutations of size $n$ is greater than $\sqrt{n}$. We prove in this paper that there exists a universal constant $n_1$ such…

Probability · Mathematics 2025-04-18 Mohamed Slim Kammoun

Let $U$ be a matrix chosen randomly, with respect to Haar measure, from the unitary group $U(d).$ We express the moments of the trace of any submatrix of $U$ as a sum over partitions whose terms count certain standard and semistandard Young…

Combinatorics · Mathematics 2007-05-23 Jonathan Novak

We introduce a recursive method to deconstruct the automorphism group of an ordered set. By connecting this method with deep results for permutation groups, we prove the Automorphism Conjecture for ordered sets of width less than or equal…

Combinatorics · Mathematics 2023-05-24 Bernd S. W. Schröder

A simple permutation is one which maps no proper non-singleton interval onto an interval. We consider the enumeration of simple permutations from several aspects. Our results include a straightforward relationship between the ordinary…

Combinatorics · Mathematics 2007-05-23 M. H. Albert , M. D. Atkinson , M. Klazar

Finding the minimum distance of linear codes is an NP-hard problem. Traditionally, this computation has been addressed by means of the design of algorithms that find, by a clever exhaustive search, a linear combination of some generating…

Information Theory · Computer Science 2020-11-02 M. P. Cuéllar , J. Gómez-Torrecillas , F. J. Lobillo , G. Navarro

We introduce and study the notion of entropy of affine permutations and prove that it coincides with the atomic length associated with the sum of the fundamental weights for a type $A$ affine root system, as defined by the first two…

Representation Theory · Mathematics 2026-03-24 Nathan Chapelier-Laget , Thomas Gerber , Nicolas Jacon , Cédric Lecouvey

An old open problem in graph drawing asks for the size of a universal point set, a set of points that can be used as vertices for straight-line drawings of all n-vertex planar graphs. We connect this problem to the theory of permutation…

Computational Geometry · Computer Science 2015-07-16 Michael J. Bannister , Zhanpeng Cheng , William E. Devanny , David Eppstein

We survey the known results about simple permutations. In particular, we present a number of recent enumerative and structural results pertaining to simple permutations, and show how simple permutations play an important role in the study…

Combinatorics · Mathematics 2008-04-18 Robert Brignall

We compute the number of ways a given permutation can be written as a product of exactly $k$ transpositions. We express this number as a linear combination of explicit geometric sequences, with coefficients which can be computed in many…

Combinatorics · Mathematics 2017-02-21 Michael Anshelevich , Matthew Gaikema , Madeline Hansalik , Songyu He , Nathan Mehlhop

Let $S_{\rm lcm}(n)$ denote the set of permutations $\pi$ of $[n]=\{1,2,\dots,n\}$ such that ${\rm lcm}[j,\pi(j)]\le n$ for each $j\in[n]$. Further, let $S_{\rm div}(n)$ denote the number of permutations $\pi$ of $[n]$ such that…

Number Theory · Mathematics 2022-06-07 Carl Pomerance

Each group G of nxn permutation matrices has a corresponding permutation polytope, P(G):=conv(G) in R^{nxn}. We relate the structure of P(G) to the transitivity of G. In particular, we show that if G has t nontrivial orbits, then…

Combinatorics · Mathematics 2007-05-23 Robert Guralnick , David Perkinson

Canon permutations are permutations of the multiset having $k$ copies of each integer between $1$ and $n$, with the property that the subsequences obtained by taking the $j$th copy of each entry, for each fixed $j$, are all the same. For…

Combinatorics · Mathematics 2024-03-25 Sergi Elizalde

We consider uniform random permutations of length $n$ conditioned to have no cycle longer than $n^\beta$ with $0<\beta<1$, in the limit of large $n$. Since in unconstrained uniform random permutations most of the indices are in cycles of…

Probability · Mathematics 2018-12-21 Volker Betz , Helge Schäfer , Dirk Zeindler

We show that all permutations in $S_n$ can be generated by affine unicritical polynomials. We use the $\operatorname{PGL}$ group structure to compute the cycle structure of permutations with low Carlitz rank. The tree structure of the group…

Number Theory · Mathematics 2021-03-22 Anna Chlopecki , Juliano Levier-Gomes , Wayne Peng , Alex Shearer , Adam Towsley

A sorting network is a shortest path from 12...n to n...21 in the Cayley graph of S_n generated by nearest-neighbour swaps. We prove that for a uniform random sorting network, as n->infinity the space-time process of swaps converges to the…

Probability · Mathematics 2011-11-10 Omer Angel , Alexander E. Holroyd , Dan Romik , Balint Virag

A superpermutation is a sequence that contains every permutation of $n$ distinct symbols as a contiguous substring. For instance, a valid example for three symbols is a sequence that contains all six permutations. This paper introduces a…

Discrete Mathematics · Computer Science 2025-05-19 Dhruv Ajmera

The reconstruction problem for permutations on $n$ elements from their erroneous patterns which are distorted by transpositions is presented in this paper. It is shown that for any $n \geq 3$ an unknown permutation is uniquely…

Combinatorics · Mathematics 2007-05-23 Elena Konstantinova , Vladimir Levenshtein , Johannes Siemons

The extension complexity of a polytope $P$ is the smallest integer $k$ such that $P$ is the projection of a polytope $Q$ with $k$ facets. We study the extension complexity of $n$-gons in the plane. First, we give a new proof that the…

Discrete Mathematics · Computer Science 2012-11-26 Samuel Fiorini , Thomas Rothvoß , Hans Raj Tiwary

We describe an algorithm, implemented in Python, which can enumerate any permutation class with polynomial enumeration from a structural description of the class. In particular, this allows us to find formulas for the number of permutations…

Combinatorics · Mathematics 2015-11-17 Cheyne Homberger , Vince Vatter

A universal cycle (u-cycle) for permutations of length $n$ is a cyclic word, any size $n$ window of which is order-isomorphic to exactly one permutation of length $n$, and all permutations of length $n$ are covered. It is known that…

Combinatorics · Mathematics 2024-08-13 Sergey Kitaev , Dun Qiu