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Main Authors: Chen, Yiming, Fan, Neil J. Y., Xiong, Rui, Yao, Ming
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2511.00980
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author Chen, Yiming
Fan, Neil J. Y.
Xiong, Rui
Yao, Ming
author_facet Chen, Yiming
Fan, Neil J. Y.
Xiong, Rui
Yao, Ming
contents In this paper, we establish a new geometric setting for bumpless pipe dreams and double Schubert polynomials. Building on the notion of bumpless pipe dream fragments, we define clan polynomials as their weight generating functions. It turns out that clan polynomials arise naturally in the equivariant geometry of ($GL_p\times GL_q$)-orbits over the flag variety $Fl_{p+q}$ parametrized by $(p,q)$-clans. Furthermore, we show that the coefficients in the equivariant Schubert expansion of the fundamental classes of ($GL_p\times GL_q$)-orbit closures are exactly clan polynomials, which resolves an open problem posed by Wyser and Yong.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00980
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bumpless Pipe Dream Fragments -- Equivariant Geometry of Clans
Chen, Yiming
Fan, Neil J. Y.
Xiong, Rui
Yao, Ming
Combinatorics
Algebraic Geometry
In this paper, we establish a new geometric setting for bumpless pipe dreams and double Schubert polynomials. Building on the notion of bumpless pipe dream fragments, we define clan polynomials as their weight generating functions. It turns out that clan polynomials arise naturally in the equivariant geometry of ($GL_p\times GL_q$)-orbits over the flag variety $Fl_{p+q}$ parametrized by $(p,q)$-clans. Furthermore, we show that the coefficients in the equivariant Schubert expansion of the fundamental classes of ($GL_p\times GL_q$)-orbit closures are exactly clan polynomials, which resolves an open problem posed by Wyser and Yong.
title Bumpless Pipe Dream Fragments -- Equivariant Geometry of Clans
topic Combinatorics
Algebraic Geometry
url https://arxiv.org/abs/2511.00980