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Related papers: Catalan functions and $k$-Schur positivity

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We prove sign-alternation of the product structure constants in the basis dual to the basis consisting of the structure sheaves of Schubert varieties in the torus-equivariant Grothendieck group of coherent sheaves on the partial flag…

Algebraic Geometry · Mathematics 2025-06-26 Joseph Compton , Shrawan Kumar

In this paper, we study equivariant vector bundles on partial flag varieties arising from Schur functors. We show that a partial flag variety with three or more steps does not admit an Ulrich bundle of this form with respect to the minimal…

Algebraic Geometry · Mathematics 2015-12-23 Izzet Coskun , Jack Huizenga , Matthew Woolf

In this short note we present a generating function computing the compactly supported Euler characteristic $\chi_c(F(X, n), K^{\boxtimes n})$ of the configuration spaces on a topologically stratified space $X$, with $K$ a constructible…

Algebraic Topology · Mathematics 2023-04-21 Louis Hainaut

Let G be a locally compact group, let X be a universal proper G-space, and let Z be a G-equivariant compactification of X that is H-equivariantly contractible for each compact subgroup H of G. Let W be the resulting boundary. Assuming the…

K-Theory and Homology · Mathematics 2015-10-23 Heath Emerson , Ralf Meyer

We give a combinatorial proof that the product of a Schubert polynomial by a Schur polynomial is a nonnegative sum of Schubert polynomials. Our proof uses Assaf's theory of dual equivalence to show that a quasisymmetric function of Bergeron…

Combinatorics · Mathematics 2014-05-13 Sami Assaf , Nantel Bergeron , Frank Sottile

Schur functions are a basis of the symmetric function ring that represent Schubert cohomology classes for Grassmannians. Replacing the cohomology ring with $K$-theory yields a rich combinatorial theory of inhomogeneous deformations, where…

Combinatorics · Mathematics 2023-05-19 Logan Crew , Oliver Pechenik , Sophie Spirkl

We introduce the notion of characteristic functions for commuting tuples of hypercontractions on Hilbert spaces, as a generalization of the notion of Sz.-Nagy and Foias characteristic functions of contractions. We present an explicit method…

Functional Analysis · Mathematics 2019-05-22 Monojit Bhattacharjee , B. Krishna Das , Jaydeb Sarkar

We give geometric descriptions of the category C_k(n,d) of rational polynomial representations of GL_n over a field k of degree d for d less than or equal to n, the Schur functor and Schur-Weyl duality. The descriptions and proofs use a…

Representation Theory · Mathematics 2014-02-07 Carl Mautner

Let $G/P$ be a complex cominuscule flag manifold. We prove a type independent formula for the torus equivariant Mather class of a Schubert variety in $G/P$, and for a Schubert variety pulled back via the natural projection $G/Q \to G/P$. We…

Algebraic Geometry · Mathematics 2020-06-11 Leonardo C. Mihalcea , Rahul Singh

We investigate chromatic symmetric functions in the relation to the algebra $\Gamma$ of symmetric functions generated by Schur $Q$-functions. We construct natural bases of $\Gamma$ in terms of chromatic symmetric functions. We also consider…

Combinatorics · Mathematics 2019-07-24 Soojin Cho , JiSun Huh , Sun-Young Nam

Motivated by the notion of nice graphs, we introduce the concept of strongly nice property, which can be used to study the Schur positivity of symmetric functions. We show that a graph and all its induced subgraphs are strongly nice if and…

Combinatorics · Mathematics 2024-08-28 Ethan Y. H. Li , Grace M. X. Li , Arthur L. B. Yang , Zhong-Xue Zhang

We consider families of quasisymmetric functions with the property that if a symmetric function $f$ is a positive sum of functions in one of these families, then f is necessarily a positive sum of Schur functions. Furthermore, in each of…

Combinatorics · Mathematics 2015-08-31 Austin Roberts

We prove the additive version of the conjecture proposed by Ginzburg and Kaledin. This conjecture states that if X/G is an orbifold modeled on a quotient of a smooth affine symplectic variety X (over C) by a finite group G\subset Aut(X) and…

Quantum Algebra · Mathematics 2007-05-23 Vasiliy Dolgushev , Pavel Etingof

Let $X$ be a smooth projective variety of dimension $n$, and let $E$ be an ample vector bundle over $X$. We show that any non-zero Schur class of $E$, lying in the cohomology group of bidegree $(n-1, n-1)$, has a representative which is…

Algebraic Geometry · Mathematics 2020-07-27 Jian Xiao

Combining the Kazarian approach to Thom polynomials via classifying spaces of singularities with the Fulton-Lazarsfeld theory of numerical positivity for ample vector bundles, we show that the coefficients of various Schur function…

Algebraic Geometry · Mathematics 2007-05-23 Piotr Pragacz , Andrzej Weber

We establish a class of Oppenheim--Schur-type inequalities for the convolutional Jury product of positive semidefinite matrices. These results extend to a causal convolutional setting the classical Schur and Oppenheim inequalities…

Functional Analysis · Mathematics 2026-02-25 Dominique Guillot , Javad Mashreghi , Prateek Kumar Vishwakarma

We prove a structure theorem for the Gromov-Witten invariants of compact Kahler surfaces with geometric genus $p_g>0$. Under the technical assumption that there is a canonical divisor that is a disjoint union of smooth components, the…

Symplectic Geometry · Mathematics 2007-05-23 Junho Lee , Thomas H. Parker

We prove that Schur classes of nef vector bundles are limits of classes that have a property analogous to the Hodge-Riemann bilinear relations. We give a number of applications, including (1) new log-concavity statements about…

Algebraic Geometry · Mathematics 2021-06-22 Julius Ross , Matei Toma

We obtain descriptions of central operator-valued Schur and Herz-Schur multipliers, akin to a classical characterisation due to Grothendieck, that reveals a close link between central (linear) multipliers and bilinear multipliers into the…

Functional Analysis · Mathematics 2021-01-05 Andrew McKee , Reyhaneh Pourshahami , Ivan G. Todorov , Lyudmila Turowska

This is a review/announcement of results concerning the connection between certain exactly solvable two-dimensional models of statistical mechanics, namely loop models, and the equivariant $K$-theory of the cotangent bundle of the…

Algebraic Geometry · Mathematics 2018-07-16 Paul Zinn-Justin