Results 31 to 40 of about 2,046 (100)
Counting occurrences of 132 in an even permutation
We study the generating function for the number of even (or odd) permutations on n letters containing exactly r ≥ 0 occurrences of a 132 pattern. It is shown that finding this function for a given r amounts to a routine check of all permutations in 𝔖2r.
Toufik Mansour
wiley +1 more source
Descent c-Wilf Equivalence [PDF]
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 +1 more source
First hitting times of simple random walks on graphs with congestion points
We derive the explicit formulas of the probability generating functions of the first hitting times of simple random walks on graphs with congestion points using group representations.
Mihyun Kang
wiley +1 more source
Equivalence classes of mesh patterns with a dominating pattern [PDF]
Two mesh patterns are coincident if they are avoided by the same set of permutations, and are Wilf-equivalent if they have the same number of avoiders of each length.
Murray Tannock, Henning Ulfarsson
doaj +1 more source
MacMahon’s statistics on higher-dimensional partitions
We study some combinatorial properties of higher-dimensional partitions which generalize plane partitions. We present a natural bijection between d-dimensional partitions and d-dimensional arrays of nonnegative integers.
Alimzhan Amanov, Damir Yeliussizov
doaj +1 more source
Combinatorics of geometrically distributed random variables: new q‐tangent and q‐secant numbers
Up‐down permutations are counted by tangent (respectively, secant) numbers. Considering words instead, where the letters are produced by independent geometric distributions, there are several ways of introducing this concept; in the limit they all coincide with the classical version. In this way, we get some new q‐tangent and q‐secant functions.
Helmut Prodinger
wiley +1 more source
n‐Color partitions with weighted differences equal to minus two
In this paper we study those n‐color partitions of Agarwal and Andrews, 1987, in which each pair of parts has weighted difference equal to −2 Results obtained in this paper for these partitions include several combinatorial identities, recurrence relations, generating functions, relationships with the divisor function and computer produced tables.
A. K. Agarwal, R. Balasubrananian
wiley +1 more source
A new class of infinite products, and Euler′s totient
We introduce some new infinite products, the simplest being where ϕk is the set of positive integers less than and relatively prime to k, valid for |y|∧|qy| both less than unity, with q ≠ 1. The idea of a q‐analogue for the Euler totient function is suggested.
Geoffrey B. Campbell
wiley +1 more source
Snow Leopard Permutations and Their Even and Odd Threads [PDF]
Caffrey, Egge, Michel, Rubin and Ver Steegh recently introduced snow leopard permutations, which are the anti-Baxter permutations that are compatible with the doubly alternating Baxter permutations. Among other things, they showed that these permutations
Eric S. Egge, Kailee Rubin
doaj +1 more source
An infinite version of the Pólya enumeration theorem
Using measure theory, the orbit counting form of Pólya′s enumeration theorem is extended to countably infinite discrete groups.
Robert A. Bekes
wiley +1 more source

