Results 1 to 10 of about 360 (61)
Enumeration of super-strong Wilf equivalence classes of permutations in the generalized factor order [PDF]
Discrete Mathematics & Theoretical Computer Science, 2019 Super-strong Wilf equivalence classes of the symmetric group ${\mathcal S}_n$ on $n$ letters, with respect to the generalized factor order, were shown by Hadjiloucas, Michos and Savvidou (2018) to be in bijection with pyramidal sequences of consecutive ...
Ioannis Michos, Christina Savvidou
doaj +3 more sources
Descent c-Wilf Equivalence [PDF]
Discrete Mathematics & Theoretical Computer Science, 2017 Let $S_n$ denote the symmetric group. For any $\sigma \in S_n$, we let $\mathrm{des}(\sigma)$ denote the number of descents of $\sigma$, $\mathrm{inv}(\sigma)$ denote the number of inversions of $\sigma$, and $\mathrm{LRmin}(\sigma)$ denote the number of
Quang T. Bach, Jeffrey B. Remmel
doaj +3 more sources
Consecutive Patterns in Inversion Sequences [PDF]
Discrete Mathematics & Theoretical Computer Science, 2019 An inversion sequence of length $n$ is an integer sequence $e=e_{1}e_{2}\dots e_{n}$ such that $0\leq e_{i}
Juan S. Auli, Sergi Elizalde
doaj +3 more sources
Enumeration of Stack-Sorting Preimages via a Decomposition Lemma [PDF]
Discrete Mathematics & Theoretical Computer Science, 2021 We give three applications of a recently-proven "Decomposition Lemma," which allows one to count preimages of certain sets of permutations under West's stack-sorting map $s$.
Colin Defant
doaj +3 more sources
Pattern avoidance for set partitions \`a la Klazar [PDF]
Discrete Mathematics & Theoretical Computer Science, 2016 In 2000 Klazar introduced a new notion of pattern avoidance in the context of set partitions of $[n]=\{1,\ldots, n\}$. The purpose of the present paper is to undertake a study of the concept of Wilf-equivalence based on Klazar's notion.
Jonathan Bloom, Dan Saracino
doaj +3 more sources
Discrete Mathematics & Theoretical Computer Science, 2019 Two permutations in a class are Wilf-equivalent if, for every size, $n$, the number of permutations in the class of size $n$ containing each of them is the same.
Michael Albert, Jinge Li
doaj +3 more sources
Operators of equivalent sorting power and related Wilf-equivalences [PDF]
Discrete Mathematics & Theoretical Computer Science, 2013 We study sorting operators $\textrm{A}$ on permutations that are obtained composing Knuth's stack sorting operator \textrmS and the reverse operator $\textrm{R}$, as many times as desired.
Michael Albert, Mathilde Bouvel
doaj +5 more sources
Enumeration of Dumont permutations avoiding certain four-letter patterns [PDF]
Discrete Mathematics & Theoretical Computer Science, 2021 In this paper, we enumerate Dumont permutations of the fourth kind avoiding or containing certain permutations of length 4. We also conjecture a Wilf-equivalence of two 4-letter patterns on Dumont permutations of the first kind.
Alexander Burstein, Opel Jones
doaj +1 more source
The Rearrangement Conjecture [PDF]
Discrete Mathematics & Theoretical Computer Science, 2014 The Rearrangement Conjecture states that if two words over $\mathbb{P}$ are Wilf-equivalent in the factor order on $\mathbb{P}^{\ast}$ then they are rearrangements of each other.
Jay Pantone, Vincent Vatter
doaj +1 more source
The 26 Wilf-equivalence classes of length five quasi-consecutive patterns [PDF]
Discrete Mathematics & Theoretical Computer Science, 2018 We present two families of Wilf-equivalences for consecutive and quasi-consecutive vincular patterns. These give new proofs of the classification of consecutive patterns of length $4$ and $5$.
Evan Chen, Shyam Narayanan
doaj +1 more source