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Related papers: Changing Bases with Pipe Dream Combinatorics

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We establish the conjecture of Reiner and Yong for an explicit combinatorial formula for the expansion of a Grothendieck polynomial into the basis of Lascoux polynomials. This expansion is a subtle refinement of its symmetric function…

Combinatorics · Mathematics 2021-06-29 Mark Shimozono , Tianyi Yu

Motivated by Stanley's ``Schubert shenanigans'' paper, commendable attempts have been made to understand the principal specializations of Schubert or Grothendieck polynomials. In this paper, we prove that when a permutation $w$ does not…

Combinatorics · Mathematics 2026-05-12 Haojun Bai , Feng Gu , Peter L. Guo , Jiaji Liu

We present computational results on principal specializations $\mathfrak{S}_w(1^n)$ of Schubert polynomials, which count reduced pipe dreams and reduced bumpless pipe dreams (RBPD). We find the first counterexample, at $n=17$, to the…

Combinatorics · Mathematics 2026-03-23 David Anderson , Greta Panova , Leonid Petrov

Grothendieck polynomials, introduced by Lascoux and Sch\"utzenberger, are certain $K$-theory representatives for Schubert varieties. Symplectic Grothendieck polynomials, described more recently by Wyser and Yong, represent the $K$-theory…

Combinatorics · Mathematics 2020-08-04 Eric Marberg , Brendan Pawlowski

In our previous work we have introduced an analogue of Robinson-Schensted-Knuth correspondence for Schubert calculus of the complete flag varieties. The objects inserted are certain biwords, the outcomes of insertion are bumpless pipe…

Combinatorics · Mathematics 2023-04-17 Daoji Huang , Pavlo Pylyavskyy

We describe an elementary convex geometric algorithm for realizing Schubert cycles in complete flag varieties by unions of faces of polytopes. For GL_n and Gelfand--Zetlin polytopes, combinatorics of this algorithm coincides with that of…

Algebraic Geometry · Mathematics 2019-02-08 Valentina Kiritchenko

Schubert polynomials for the classical groups were defined by S.Billey and M.Haiman in 1995; they are polynomial representatives of Schubert classes in a full flag variety of a classical group. We provide a combinatorial description for…

Combinatorics · Mathematics 2022-09-15 Evgeny Smirnov , Anna Tutubalina

Matrix Schubert varieties are the closures of the orbits of $B\times B$ acting on all $n\times n$ matrices, where $B$ is the group of invertible lower triangular matrices. Extending work of Fulton, Knutson and Miller identified a Gr\"obner…

Algebraic Geometry · Mathematics 2022-06-17 Eric Marberg , Brendan Pawlowski

Schubert polynomials were introduced in the context of the geometry of flag varieties. This paper investigates some of the connections not yet understood between several combinatorial structures for the construction of Schubert polynomials;…

Combinatorics · Mathematics 2007-05-23 Cristian Lenart

We give an explicit formula for the degree of the Grothendieck polynomial of a Grassmannian permutation and a closely related formula for the Castelnuovo-Mumford regularity of the Schubert determinantal ideal of a Grassmannian permutation.…

Combinatorics · Mathematics 2020-07-30 Jenna Rajchgot , Yi Ren , Colleen Robichaux , Avery St. Dizier , Anna Weigandt

We recall the lower-upper varieties from [Knutson '05] and give a formula for their equivariant cohomology classes, as a sum over generic pipe dreams. We recover as limits the classic and bumpless pipe dream formulae for double Schubert…

Combinatorics · Mathematics 2024-11-19 Allen Knutson , Paul Zinn-Justin

Grothendieck polynomials were introduced by Lascoux and Sch\"utzenberger, and they play an important role in K-theoretic Schubert calculus. In this paper, we give a new definition of double stable Grothendieck polynomials based on an…

Algebraic Topology · Mathematics 2018-11-07 Richard Rimanyi , Andras Szenes

Fulton's universal Schubert polynomials give cohomology formulas for a class of degeneracy loci, which generalize Schubert varieties. The K-theoretic quiver formula of Buch expresses the structure sheaves of these loci as integral linear…

Combinatorics · Mathematics 2016-09-07 Anders Skovsted Buch , Andrew Kresch , Harry Tamvakis , Alexander Yong

Pechenik, Speyer and Weigandt defined a statistic $\mathsf{rajcode}(\cdot)$ on permutations which characterizes the leading monomial in top degree components of double Grothendieck polynomials. Their proof is combinatorial: They showed…

Combinatorics · Mathematics 2023-12-05 Chen-An Chou , Tianyi Yu

Grothendieck polynomials are important objects in the study of the $K$-theory of flag varieties. Their many remarkable properties have been studied in the context of algebraic geometry and tableaux combinatorics. We explore a new tool,…

Combinatorics · Mathematics 2017-11-15 J. Allman , R. Rimanyi

We give degree formulas for Grothendieck polynomials indexed by vexillary permutations and $1432$-avoiding permutations via tableau combinatorics. These formulas generalize a formula for degrees of symmetric Grothendieck polynomials which…

Combinatorics · Mathematics 2022-12-05 Jenna Rajchgot , Colleen Robichaux , Anna Weigandt

The variety of complete quadrics is the wonderful compactification of $GL_n/O_n$ and admits a cell decomposition into Borel orbits indexed by combinatorial objects called $\mu$-involutions. We study Coxeter-theoretic properties of…

Combinatorics · Mathematics 2026-04-07 Jack Chen-An Chou , Zachary Hamaker

Grothendieck polynomials $\mathfrak{G}_w$ of permutations $w\in S_n$ were introduced by Lascoux and Sch\"utzenberger in 1982 as a set of distinguished representatives for the K-theoretic classes of Schubert cycles in the K-theory of the…

Combinatorics · Mathematics 2022-01-25 Karola Mészáros , Linus Setiabrata , Avery St. Dizier

We prove a formula for double Schubert and Grothendieck polynomials specialized to two rearrangements of the same set of variables. Our formula generalizes the usual formulas for Schubert and Grothendieck polynomials in terms of RC-graphs,…

Algebraic Geometry · Mathematics 2007-05-23 Anders S. Buch , Richard Rimanyi

The flagged refined stable Grothendieck polynomials of skew shapes generalize several polynomials like stable Grothendieck polynomials, flagged skew Schur polynomials. In this paper, we provide a combinatorial expansion of the flagged…

Combinatorics · Mathematics 2026-02-05 Siddheswar Kundu