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This paper is concerned with two generalizations of the Hopf algebra of symmetric functions that have more or less recently appeared. The Hopf algebra of noncommutative symmetric functions and its dual, the Hopf algebra of quasisymmetric…

Quantum Algebra · Mathematics 2007-05-23 Michiel Hazewinkel

We make a systematic study of a new combinatorial construction called a dual equivalence graph. We axiomatize these graphs and prove that their generating functions are symmetric and Schur positive. This provides a universal method for…

Combinatorics · Mathematics 2020-03-05 Sami H. Assaf

We construct a new class of operators that act on symmetric functions with two deformation parameters $q$ and $t$. Our combinatorial construction associates each operator with a specific lattice path, whose steps alternate between moving up…

Combinatorics · Mathematics 2025-06-09 Houcine Ben Dali , Valentin Bonzom , Maciej Dołęga

The product $s_\mu s_\nu$ of two Schur functions is one of the most famous examples of a Schur-positive function, i.e. a symmetric function which, when written as a linear combination of Schur functions, has all positive coefficients. We…

Combinatorics · Mathematics 2007-05-23 Francois Bergeron , Peter McNamara

Quasisymmetric functions in superspace were introduced as a natural extension of classical quasisymmetric functions involving both commuting and anticommuting variables. In this paper, we first provide a characterization of the algebra of…

Combinatorics · Mathematics 2026-04-09 Diego Arcis , Camilo González , Sebastián Márquez

We introduce new families of cylindric symmetric functions as subcoalgebras in the ring of symmetric functions $\Lambda$ (viewed as a Hopf algebra) which have non-negative structure constants. Combinatorially these cylindric symmetric…

Combinatorics · Mathematics 2019-07-05 Christian Korff , David Palazzo

We construct a generalization of the theory of symmetric functions involving functions of commuting and anticommuting (Grassmannian) variables. These new functions, called symmetric functions in superspace, are invariant under the diagonal…

Combinatorics · Mathematics 2007-05-23 P. Desrosiers , L. Lapointe , P. Mathieu

We show that certain differences of products of $P$-partition generating functions are positive in the basis of fundamental quasi-symmetric functions L_\alpha. This result interpolates between recent Schur positivity and monomial positivity…

Combinatorics · Mathematics 2007-05-23 Thomas Lam , Pavlo Pylyavskyy

We construct a lift of Schur's Q-functions to the peak algebra of the symmetric group, called the noncommutative Schur Q-functions, and extract from them a new natural basis with several nice properties such as the positive right-Pieri…

Combinatorics · Mathematics 2020-09-08 Naihuan Jing , Yunnan Li

We define a new basis of quasisymmetric functions, the row-strict dual immaculate functions, as the generating function of a particular set of tableaux. We establish that this definition gives a function that can also be obtained by…

Combinatorics · Mathematics 2025-09-09 Elizabeth Niese , Sheila Sundaram , Stephanie van Willigenburg , Julianne Vega , Shiyun Wang

Reiner, Shaw and van Willigenburg showed that if two skew Schur functions s_A and s_B are equal, then the skew shapes A and B must have the same "row overlap partitions." Here we show that these row overlap equalities are also implied by a…

Combinatorics · Mathematics 2014-02-13 Peter R. W. McNamara

H.Choi-D.Kim-S.J.Lee and S.J.Lee introduced a new kind of tableaux, semistandard oscillating tableaux (SSOT), around 2024 in the context of Lusztig $q$-weight multiplicities, KR crystals and King tableaux. In this paper, we study generating…

Combinatorics · Mathematics 2026-01-27 Masato Kobayashi , Tomoo Matsumura , Shogo Sugimoto

A new descent set statistic on involutions, defined geometrically via their interpretation as matchings, is introduced in this paper, and shown to be equi-distributed with the standard one. This concept is then applied to construct explicit…

Combinatorics · Mathematics 2023-01-03 Ron M. Adin , Yuval Roichman

The ring of symmetric functions occupies a central place in algebraic combinatorics, with a particularly notable role in Schubert calculus, where the standard cell decompositions of Grassmannians yield the celebrated family of Schur…

Algebraic Topology · Mathematics 2023-07-20 Oliver Pechenik , Matthew Satriano

The question of classifying when two skew Schur functions are equal is a substantial open problem, which remains unsolved for over a century. In 2022, Aliniaeifard, Li and van Willigenburg introduced skew Schur functions in noncommuting…

Combinatorics · Mathematics 2025-02-05 Emma Yu Jin , Stephanie van Willigenburg

Consider the algebra Q<<x_1,x_2,...>> of formal power series in countably many noncommuting variables over the rationals. The subalgebra Pi(x_1,x_2,...) of symmetric functions in noncommuting variables consists of all elements invariant…

Combinatorics · Mathematics 2007-05-23 Mercedes H. Rosas , Bruce E. Sagan

In his work on P-partitions, Stembridge defined the algebra of peak functions Pi, which is both a subalgebra and a retraction of the algebra of quasi-symmetric functions. We show that Pi is closed under coproduct, and therefore a Hopf…

Combinatorics · Mathematics 2016-11-08 Nantel Bergeron , Stefan Mykytiuk , Frank Sottile , Stephanie van Willigenburg

We extend the notion of ascent-compatibility from symmetric groups to all Coxeter groups, thereby providing a type-independent framework for constructing families of modules of $0$-Hecke algebras. We apply this framework in type $B$ to give…

Combinatorics · Mathematics 2024-04-09 Colin Defant , Dominic Searles

We show that with the appropriate choice of coproduct, the type B quasisymmetric functions form a Hopf algebra, and the recently introduced type B peak functions form a Hopf subalgebra.

Combinatorics · Mathematics 2007-05-23 Samuel K. Hsiao , T. Kyle Petersen

We introduce a quasisymmetric refinement of Stanley's chromatic symmetric function. We derive refinements of both Gasharov's Schur-basis expansion of the chromatic symmetric function and Chow's expansion in Gessel's basis of fundamental…

Combinatorics · Mathematics 2016-03-30 John Shareshian , Michelle L. Wachs