Castelnuovo–Mumford regularity of matrix Schubert varieties

O Pechenik, DE Speyer, A Weigandt - Selecta Mathematica, 2024 - Springer
Matrix Schubert varieties are affine varieties arising in the Schubert calculus of the complete
flag variety. We give a formula for the Castelnuovo–Mumford regularity of matrix Schubert …

From generalized permutahedra to Grothendieck polynomials via flow polytopes

K Mészáros, A St Dizier - Algebraic Combinatorics, 2020 - numdam.org
We study a family of dissections of flow polytopes arising from the subdivision algebra. To
each dissection of a flow polytope, we associate a polynomial, called the left-degree …

The permutahedral variety, mixed Eulerian numbers, and principal specializations of Schubert polynomials

P Nadeau, V Tewari - International Mathematics Research …, 2023 - academic.oup.com
We compute the expansion of the cohomology class of the permutahedral variety in the
basis of Schubert classes. The resulting structure constants are expressed as a sum of …

Schubert polynomials, pipe dreams, equivariant classes, and a co-transition formula

A Knutson - Facets of Algebraic Geometry: Volume 2: A Collection …, 2022 - books.google.com
We give a new proof that three families of polynomials coincide: the double Schubert
polynomials of Lascoux and Schutzenberger defined by divided difference operators, the …

Subword Complexes and Kalai's Conjecture on Reconstruction of Spheres

C Ceballos, J Doolittle - arXiv preprint arXiv:2206.15461, 2022 - arxiv.org
A famous theorem in polytope theory states that the combinatorial type of a simplicial
polytope is completely determined by its facet-ridge graph. This celebrated result was …

Flow polytopes with Catalan volumes

S Corteel, JS Kim, K Mészáros - Comptes Rendus. Mathématique, 2017 - numdam.org
We underscore the wealth of flow polytopes with product formulas for volumes. The natural
question arising from our study and previous works [1–3, 8, 10, 11, 13, 14] is: is there a …

Counting integer points of flow polytopes

K Kapoor, K Mészáros, L Setiabrata - Discrete & Computational Geometry, 2021 - Springer
Abstract The Baldoni–Vergne volume and Ehrhart polynomial formulas for flow polytopes
are significant in at least two ways. On one hand, these formulas are in terms of Kostant …

Matrix Schubert varieties, binomial ideals, and reduced Gr\" obner bases

A Stelzer - arXiv preprint arXiv:2306.03006, 2023 - arxiv.org
We prove a sharp lower bound on the number of terms in an element of the reduced Gr\"
obner basis of a Schubert determinantal ideal $ I_w $ under the term order of [Knutson …

Degrees of P-Grothendieck polynomials and regularity of Pfaffian varieties

O Pechenik, MS Denis - arXiv preprint arXiv:2405.17645, 2024 - arxiv.org
We prove a formula for the degrees of Ikeda and Naruse's $ P $-Grothendieck polynomials
using combinatorics of shifted tableaux. We show this formula can be used in conjunction …

Complexity of the usual torus action on Kazhdan-Lusztig varieties

M Donten-Bury, L Escobar, I Portakal - arXiv preprint arXiv:2111.13540, 2021 - arxiv.org
We investigate the class of Kazhdan-Lusztig varieties, and its subclass of matrix Schubert
varieties, endowed with a naturally defined torus action. Writing a matrix Schubert variety …