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We study new statistics on permutations that are variations on the descent and the inversion statistics. In particular, we consider the alternating descent set of a permutation sigma = sigma_1sigma_2...sigma_n defined as the set of indices…

Combinatorics · Mathematics 2008-04-14 Denis Chebikin

The number of inversions is a statistic on permutation groups measuring the degree to which the entries of a permutation are out of order. We provide a generalization of that statistic by introducing the statistic number of pseudoinversions…

Combinatorics · Mathematics 2019-06-26 Patrick Rabarison , Hery Randriamaro

Natural q analogues of classical statistics on the symmetric groups $S_n$ are introduced; parameters like: the q-length, the q-inversion number, the q-descent number and the q-major index. MacMahon's theorem about the equi-distribution of…

Combinatorics · Mathematics 2007-05-23 Amitai Regev , Yuval Roichman

Permutations that avoid given patterns have been studied in great depth for their connections to other fields of mathematics, computer science, and biology. From a combinatorial perspective, permutation patterns have served as a unifying…

Combinatorics · Mathematics 2023-06-22 Sylvie Corteel , Megan A. Martinez , Carla D. Savage , Michael Weselcouch

We introduce and study new refinements of inversion statistics for permutations, such as k-step inversions, (the number of inversions with fixed position differences) and non-inversion sums (the sum of the differences of positions of the…

Combinatorics · Mathematics 2012-01-13 Joshua Sack , Henning Úlfarsson

We consider the joint distribution of the area and perimeter statistics on the set I_n of inversion sequences of length n represented as bargraphs. Functional equations for both the ordinary and exponential generating functions are derived…

Combinatorics · Mathematics 2022-03-16 Toufik Mansour , Mark Shattuck

Inversion sequences are integer sequences $e=e_{1}e_{2}\dots e_{n}$ such that $0\leq e_{i}<i$ for each $i$. The study of patterns in inversion sequences was initiated by Corteel--Martinez--Savage--Weselcouch and Mansour--Shattuck in the…

Combinatorics · Mathematics 2019-06-19 Juan S. Auli , Sergi Elizalde

Arslan, Altoum, and Zaarour introduced an inversion statistic for generalized symmetric groups. In this work, we study the distribution of this statistic over colored permutations, including derangements and involutions. By establishing a…

Combinatorics · Mathematics 2025-05-06 Moussa Ahmia , José L. Ramírez , Diego Villamizar

In this research announcement we present a new q-analog of a classical formula for the exponential generating function of the Eulerian polynomials. The Eulerian polynomials enumerate permutations according to their number of descents or…

Combinatorics · Mathematics 2007-05-23 John Shareshian , Michelle L. Wachs

Two well-known distributions in the study of permutation statistics are the Mahonian and Eulerian distributions. Mahonian statistics include the major index MAJ and the number of inversions INV, while examples of Eulerian statistics are the…

Combinatorics · Mathematics 2024-12-19 Frederick Butler

We introduce the notion of a weighted inversion statistic on the symmetric group, and examine its distribution on each conjugacy class. Our work generalizes the study of several common permutation statistics, including the number of…

Combinatorics · Mathematics 2023-05-18 Jesse Campion Loth , Michael Levet , Kevin Liu , Eric Nathan Stucky , Sheila Sundaram , Mei Yin

In the work of Varchenko, Zagier, Thibon, and Reiner, Saliola, Welker, linear algebraic properties of the multiplication map on the group algebra of the group algebra element are studied, which is the sum over all permutations weighted by…

Combinatorics · Mathematics 2011-04-21 Hery Randriamaro

We introduce a new permutation statistic, namely, the number of cycles of length $q$ consisting of consecutive integers, and consider the distribution of this statistic among the permutations of $\{1,2,...,n\}$. We determine explicit…

Combinatorics · Mathematics 2015-03-17 Richard A. Brualdi , Emeric Deutsch

In this paper, we compute and demonstrate the equivalence of the joint distribution of the first letter and descent statistics on six avoidance classes of permutations corresponding to two patterns of length four. This distribution is in…

Combinatorics · Mathematics 2021-05-19 Toufik Mansour , Mark Shattuck

The descent set D(w) of a permutation w of 1,2,...,n is a standard and well-studied statistic. We introduce a new statistic, the connectivity set C(w), and show that it is a kind of dual object to D(w). The duality is stated in terms of the…

Combinatorics · Mathematics 2007-05-23 Richard P. Stanley

An inversion sequence of length $n$ is an integer sequence $e=e_{1}e_{2}\dots e_{n}$ such that $0\leq e_{i}<i$ for each $i$. Corteel--Martinez--Savage--Weselcouch and Mansour--Shattuck began the study of patterns in inversion sequences,…

Combinatorics · Mathematics 2023-06-22 Juan S. Auli , Sergi Elizalde

We derive a generating function for the number of integer compositions of $n$ into $k$ parts (i.e., $k$-compositions of $n$) with a given number of inversions, and obtain similar results for $k$-compositions of $n$ with a given number of…

General Mathematics · Mathematics 2026-05-21 E. G. Santos

We introduce new natural generalizations of the classical descent and inversion statistics for permutations, called width-$k$ descents and width-$k$ inversions. These variations induce generalizations of the excedance and major statistics,…

Combinatorics · Mathematics 2017-01-18 Robert Davis

Given a permutation statistic $\operatorname{st}$, define its inverse statistic $\operatorname{ist}$ by $\operatorname{ist}(\pi):=\operatorname{st}(\pi^{-1})$. We give a general approach, based on the theory of symmetric functions, for…

Combinatorics · Mathematics 2024-11-13 Ira M. Gessel , Yan Zhuang

The motivation of this paper is to investigate the joint distribution of succession and Eulerian statistics. We first investigate the enumerators for the joint distribution of descents, big ascents and successions over all permutations in…

Combinatorics · Mathematics 2024-01-09 Shi-Mei Ma , Hao Qi , Jean Yeh , Yeong-Nan Yeh
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