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Bibliographic Details
Main Author: Yu, Tianyi
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.05904
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author Yu, Tianyi
author_facet Yu, Tianyi
contents Schubert polynomials are distinguished representatives of Schubert cycles in the cohomology of the flag variety. In the spirit of Bergeron and Sottile, we use the Bruhat order to give $(n-1)!$ different combinatorial formulas for the Schubert polynomial of a permutation in $S_n$. By work of Lenart and Sottile, one extreme of the formulas recover the classical Pipedream (PD) formula. We prove the other extreme corresponds to Bumpless pipedreams (BPDs). We give two applications of this perspective to view BPDs: Using the Fomin-Kirrilov algebra, we solve the problem of finding a BPD analogue of Fomin and Stanley's algebraic construction on PDs; We also establish a bijection between PDs and BPDs using Lenart's growth diagram, which conjectually agrees with the existing bijection of Gao and Huang.
format Preprint
id arxiv_https___arxiv_org_abs_2407_05904
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Embedding bumpless pipedreams as Bruhat chains
Yu, Tianyi
Combinatorics
Schubert polynomials are distinguished representatives of Schubert cycles in the cohomology of the flag variety. In the spirit of Bergeron and Sottile, we use the Bruhat order to give $(n-1)!$ different combinatorial formulas for the Schubert polynomial of a permutation in $S_n$. By work of Lenart and Sottile, one extreme of the formulas recover the classical Pipedream (PD) formula. We prove the other extreme corresponds to Bumpless pipedreams (BPDs). We give two applications of this perspective to view BPDs: Using the Fomin-Kirrilov algebra, we solve the problem of finding a BPD analogue of Fomin and Stanley's algebraic construction on PDs; We also establish a bijection between PDs and BPDs using Lenart's growth diagram, which conjectually agrees with the existing bijection of Gao and Huang.
title Embedding bumpless pipedreams as Bruhat chains
topic Combinatorics
url https://arxiv.org/abs/2407.05904