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In 2007 Sami Assaf introduced dual equivalence graphs as a method for demonstrating that a quasisymmetric function is Schur positive. The method involves the creation of a graph whose vertices are weighted by Ira Gessel's fundamental…

Combinatorics · Mathematics 2015-03-13 Austin Roberts

We give an explicit combinatorial formula for the Schur expansion of Macdonald polynomials indexed by partitions with second part at most two. This gives a uniform formula for both hook and two column partitions. The proof comes as a…

Combinatorics · Mathematics 2017-03-23 Sami Assaf

Two mesh patterns are coincident if they are avoided by the same set of permutations. In this paper, we provide necessary conditions for this coincidence, which include having the same set of enclosed diagonals. This condition is sufficient…

Combinatorics · Mathematics 2016-05-27 Anders Claesson , Bridget Eileen Tenner , Henning Ulfarsson

The Schur polynomials $s_{\lambda}$ are essential in understanding the representation theory of the general linear group. They also describe the cohomology ring of the Grassmannians. For $\rho = (n, n-1, \dots, 1)$ a staircase shape and…

Combinatorics · Mathematics 2021-10-05 Fiona Abney-McPeek , Serena An , Jakin Ng

We present a single operation for constructing skew diagrams whose corresponding skew Schur functions are equal. This combinatorial operation naturally generalises and unifies all results of this type to date. Moreover, our operation…

Combinatorics · Mathematics 2012-02-01 Peter McNamara , Stephanie van Willigenburg

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. By constructing a graph on ribbon…

Combinatorics · Mathematics 2013-10-24 Sami H. Assaf

We compute the Schur indices in the presence of some line operators based on our con- jectural formula introduced in [1]. In particular, we focus on the rank 1 superconformal field theories with the enhanced global symmetry and the free…

High Energy Physics - Theory · Physics 2017-02-02 Noriaki Watanabe

We show that canonical bases in $\dot{U}(\mathfrak{sl}_n)$ and the Schur algebra are compatible; in fact we extend this result to $p$-canonical bases. This follows immediately from a fullness result from a functor categorifying this map. In…

Representation Theory · Mathematics 2017-11-15 Ben Webster

We use dual equivalence to give a short, combinatorial proof that Stanley symmetric functions are Schur positive. We introduce weak dual equivalence, and use it to give a short, combinatorial proof that Schubert polynomials are key…

Combinatorics · Mathematics 2017-02-15 Sami Assaf

We determine the precise conditions under which any skew Schur function is equal to a Schur function over both infinitely and finitely many variables.

Combinatorics · Mathematics 2007-06-22 Stephanie van Willigenburg

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

We give another proof for the (-1)-enumeration of self-complementary plane partitions with at least one odd side-length by specializing a certain Schur function identity. The proof is analogous to Stanley's proof for the ordinary…

Combinatorics · Mathematics 2007-05-23 Theresia Eisenkölbl

An explicit rule is given for the product of the degree two class with an arbitrary Schubert class in the torus-equivariant homology of the affine Grassmannian. In addition a Pieri rule (the Schubert expansion of the product of a special…

Combinatorics · Mathematics 2011-05-27 Thomas Lam , Mark Shimozono

We find a simple criterion for the equality $Q_\lambda=Q_{\mu/\nu}$ where $Q_\lambda$ and $Q_{\mu/\nu}$ are Schur's Q-functions on infinitely many variables.

Combinatorics · Mathematics 2007-05-23 Hadi Salmasian

Determining if a symmetric function is Schur-positive is a prevalent and, in general, a notoriously difficult problem. In this paper we study the Schur-positivity of a family of symmetric functions. Given a partition \lambda, we denote by…

Combinatorics · Mathematics 2013-10-11 Cristina Ballantine , Rosa Orellana

Dual equivalence graphs are a powerful tool in symmetric function theory that provide a general framework for proving that a given quasisymmetric function is symmetric and Schur positive. In this paper, we study a larger family of graphs…

Combinatorics · Mathematics 2017-04-25 Sami Assaf

We prove that ribbons, i.e. double structures associated with a line bundle $\SE$ over its reduced support, a smooth irreducible projective curve of arbitrary genus, are smoothable if their arithmetic genus is greater than or equal to $3 $…

Algebraic Geometry · Mathematics 2007-05-23 Miguel Gonzalez

In this article we study a theory of support varieties over a skew complete intersection $R$, i.e. a skew polynomial ring modulo an ideal generated by a sequence of regular normal elements. We compute the derived braided Hochschild…

Rings and Algebras · Mathematics 2021-02-01 Luigi Ferraro , W. Frank Moore , Josh Pollitz

We introduce a shifted analogue of the ribbon tableaux defined by James and Kerber. For any positive integer $k$, we give a bijection between the $k$-ribbon fillings of a shifted shape and regular fillings of a $\lfloor k/2\rfloor$-tuple of…

Combinatorics · Mathematics 2025-04-08 Ezgi Kantarcı Oğuz

By considering type B analogs of permutations and tableaux, we extend abstract dual equivalence to type B in two directions. In one direction, we define involutions on signed permutations and shifted tableaux that give a weak dual…

Combinatorics · Mathematics 2020-03-05 Sami Assaf