29 citations · 226 across the 51 of their papers we have counts for
7 papers · 1 filter
Restricted Motzkin permutations, Motzkin paths, continued fractions, and Chebyshev polynomials
Sergi Elizalde, Toufik Mansour
We say that a permutation is a Motzkin permutation if it avoids 132 and there do not exist such that . We study the distribution of several statistics in…
Restricted Dumont permutations, Dyck paths, and noncrossing partitions
Alexander Burstein, Sergi Elizalde, Toufik Mansour
We complete the enumeration of Dumont permutations of the second kind avoiding a pattern of length 4 which is itself a Dumont permutation of the second kind. We also consider some…
Partially ordered patterns and compositions
Silvia Heubach, Sergey Kitaev, Toufik Mansour
A partially ordered (generalized) pattern (POP) is a generalized pattern some of whose letters are incomparable, an extension of generalized permutation patterns introduced by Babs…
A generalization of boson normal ordering
Toufik Mansour, Matthias Schork, Simone Severini
In this paper we define generalizations of boson normal ordering. These are based on the number of contractions whose vertices are next to each other in the linear representation o…
Noncrossing normal ordering for functions of boson operators
Toufik Mansour, Matthias Schork, Simone Severini
Normally ordered forms of functions of boson operators are important in many contexts in particular concerning Quantum Field Theory and Quantum Optics. Beginning with the seminal w…
Wilf classification of three and four letter signed patterns
W. M. B. Dukes, T. Mansour, A. Reifegerste
We give some new Wilf equivalences for signed patterns which allow the complete classification of signed patterns of lengths three and four. The problem is considered for pattern a…