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We introduce a new basis for quasisymmetric functions, which arise from a specialization of nonsymmetric Macdonald polynomials to standard bases, also known as Demazure atoms. Our new basis is called the basis of quasisymmetric Schur…

Combinatorics · Mathematics 2010-11-30 J. Haglund , K. Luoto , S. Mason , S. van Willigenburg

For a generalized permutohedron $Q$ the enumerator $F(Q)$ of positive lattice points in interiors of maximal cones of the normal fan $\Sigma_Q$ is a quasisymmetric function. We describe this function for the class of nestohedra as a Hopf…

Combinatorics · Mathematics 2017-05-18 Vladimir Grujić

Mason and Remmel introduced a basis for quasisymmetric functions known as the row-strict quasisymmetric Schur functions. This basis is generated combinatorially by fillings of composition diagrams that are analogous to the row-strict…

Combinatorics · Mathematics 2021-05-31 Sarah K. Mason , Elizabeth Niese

Via duality of Hopf algebras, there is a direct association between peak quasisymmetric functions and enumeration of chains in Eulerian posets. We study this association explicitly, showing that the notion of $\cd$-index, long studied in…

Combinatorics · Mathematics 2007-06-26 Louis J. Billera , Samuel K. Hsiao , Stephanie van Willigenburg

We introduce a family of quasisymmetric functions called {\em Eulerian quasisymmetric functions}, which have the property of specializing to enumerators for the joint distribution of the permutation statistics, major index and excedance…

Combinatorics · Mathematics 2008-05-19 John Shareshian , Michelle L. Wachs

In our previous works we introduced a $q$-deformation of the generating functions for enriched $P$-partitions. We call the evaluation of this generating functions on labelled chains, the $q$-fundamental quasisymmetric functions. These…

Combinatorics · Mathematics 2024-10-30 Darij Grinberg , Ekaterina A. Vassilieva

Quasi-symmetric functions show up in an approach to solve the Kadomtsev-Petviashvili (KP) hierarchy. This moreover features a new nonassociative product of quasi-symmetric functions that satisfies simple relations with the ordinary product…

Mathematical Physics · Physics 2009-01-19 Aristophanes Dimakis , Folkert Muller-Hoissen

Egge, Loehr and Warrington gave in \cite{ELW} a combinatorial formula that permits to convert the expansion of a symmetric function, homogeneous of degree $n$, in terms of Gessel's fundamental quasisymmetric functions into an expansion in…

Combinatorics · Mathematics 2018-02-28 Adriano Garsia , Jeffrey Remmel

Given an element in a finite-dimensional real vector space, $V$, that is a nonnegative linear combination of basis vectors for some basis $B$, we compute the probability that it is furthermore a nonnegative linear combination of basis…

Combinatorics · Mathematics 2021-03-29 Rebecca Patrias , Stephanie van Willigenburg

The fundamental quasisymmetric functions in superspace are a generalization of the fundamental quasisymmetric functions involving anticommuting variables. We obtain the action of the product, coproduct, and antipode on the fundamental…

Combinatorics · Mathematics 2024-11-21 Susanna Fishel , Jessica Gatica , Luc Lapointe , Maria Elena Pinto

We introduce a family of quasisymmetric functions called {\em Eulerian quasisymmetric functions}, which specialize to enumerators for the joint distribution of the permutation statistics, major index and excedance number on permutations of…

Combinatorics · Mathematics 2010-08-24 John Shareshian , Michelle L. Wachs

We introduce and study a family of inhomogeneous symmetric functions which we call the Frobenius-Schur functions. These functions are indexed by partitions and differ from the conventional Schur functions in lower terms only. Our interest…

Combinatorics · Mathematics 2007-05-23 Grigori Olshanski , Amitai Regev , Anatoly Vershik

Characterizing sets of permutations whose associated quasisymmetric function is symmetric and Schur-positive is a long-standing problem in algebraic combinatorics. In this paper we present a general method to construct Schur-positive sets…

Combinatorics · Mathematics 2016-11-01 Sergi Elizalde , Yuval Roichman

We prove two conjectures of Shareshian and Wachs about Eulerian quasisymmetric functions and polynomials. The first states that the cycle type Eulerian quasisymmetric function $Q_{\lambda,j}$ is Schur-positive, and moreover that the…

Combinatorics · Mathematics 2011-11-10 Anthony Henderson , Michelle L. Wachs

We define a number of related combinatorial objects, each of which possesses a surprising symmetry. We include several applications such as a combinatorial explanation for certain fixed points of the involution $\omega$ on the ring of…

Combinatorics · Mathematics 2018-09-13 Graham Hawkes

We begin by deriving an action of the 0-Hecke algebra on standard reverse composition tableaux and use it to discover 0-Hecke modules whose quasisymmetric characteristics are the natural refinements of Schur functions known as…

Representation Theory · Mathematics 2015-09-11 Vasu V. Tewari , Stephanie J. van Willigenburg

We introduce a ring of noncommutative shifted symmetric functions based on an integer-indexed sequence of shift parameters. Using generating series and quasideterminants, this multiparameter approach produces deformations of the ring of…

Rings and Algebras · Mathematics 2023-05-04 Robert Laugwitz , Vladimir Retakh

Cylindric skew Schur functions, which are a generalisation of skew Schur functions, arise naturally in the study of P-partitions. Also, recent work of A. Postnikov shows they have a strong connection with a problem of considerable current…

Combinatorics · Mathematics 2007-05-23 Peter McNamara

Cylindric skew Schur functions, a generalization of skew Schur functions, are closely related to the famous problem finding a combinatorial formula for the 3-point Gromov-Witten invariants of Grassmannian. In this paper, we prove cylindric…

Combinatorics · Mathematics 2017-06-15 Seung Jin Lee

The involution Stanley symmetric functions $\hat{F}_y$ are the stable limits of the analogues of Schubert polynomials for the orbits of the orthogonal group in the flag variety. These symmetric functions are also generating functions for…

Combinatorics · Mathematics 2017-11-10 Zachary Hamaker , Eric Marberg , Brendan Pawlowski