Results 31 to 40 of about 331 (46)
Two permutation classes enumerated by the central binomial coefficients [PDF]
, 2013 We define a map between the set of permutations that avoid either the four patterns $3214,3241,4213,4231$ or $3124,3142,4123,4132$, and the set of Dyck prefixes.
Barnabei, Marilena +2 more
core +1 more source
A generalization of the "probléme des rencontres" [PDF]
, 2018 In this paper, we study a generalization of the classical \emph{probl\'eme des rencontres} (\emph{problem of coincidences}), consisting in the enumeration of all permutations $ \pi \in \SS_n $ with $k$ fixed points, and, in particular, in the ...
Capparelli, Stefano +3 more
core
Sums of quadratic half integer harmonic numbers of alternating type
, 2016 Half integer values of quadratic harmonic numbers and reciprocal binomial coefficients sums are investigated in this paper. Closed form representations of double integral expressions are developed in terms of special functions.
A. Sofo
semanticscholar +1 more source
Pattern Popularity in 132-Avoiding Permutations [PDF]
, 2012 The popularity of a pattern p is the total number of copies of p within all permutations of a set. We address popularity in the set of 132-avoidng permutations.
Rudolph, Kate
core
Pattern Count on Multiply Restricted Permutations [PDF]
, 2013 Previous work has studied the pattern count on singly restricted permutations. In this work, we focus on patterns of length 3 in multiply restricted permutations, especially for double and triple pattern-avoiding permutations. We derive explicit formulae
Zhao, Alina F. Y.
core
Ascent Sequences Avoiding Pairs of Patterns [PDF]
, 2014 Ascent sequences were introduced by Bousquet-Melou et al. in connection with (2+2)-avoiding posets and their pattern avoidance properties were first considered by Duncan and Steingrímsson.
Baxter, Andrew M, Pudwell, Lara
core +4 more sources
Web matrices : structural properties and generating combinatorial identities [PDF]
, 2016 In this paper we present new results for the combinatorics of web diagrams and web worlds. These are discrete objects that arise in the physics of calculating scattering amplitudes in non-abelian gauge theories.
Dukes, Mark, White, Chris D.
core +1 more source
. We study the descent distribution over the set of centrosymmetric permutations that avoid a pattern of length 3. In the most puzzling case, namely, τ = 123 and n even, our main tool is a bijection that associates a Dyck pre x of length 2n to every ...
Flavio Bonetti +2 more
core
The Eulerian numbers on restricted centrosymmetric permutations
, 2009 We study the descent distribution over the set of centrosymmetric permutations that avoid the pattern of length 3. Our main tool in the most puzzling case, namely, $\tau=123$ and $n$ even, is a bijection that associates a Dyck prefix of length $2n$ to ...
Barnabei, Marilena +2 more
core
Set-Valued Tableaux & Generalized Catalan Numbers
, 2017 Standard set-valued Young tableaux are a generalization of standard Young tableaux in which cells may contain more than one integer, with the added conditions that every integer at position $(i,j)$ must be smaller than every integer at positions $(i,j+1)$
Drube, Paul
core