Bumpless pipe dreams encode Gröbner geometry of Schubert polynomials

Fuente: arXiv
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Auteurs principaux: Klein, Patricia, Weigandt, Anna
Format: Preprint
Publié: 2021
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author Klein, Patricia
Weigandt, Anna
author_facet Klein, Patricia
Weigandt, Anna
contents In their study of infinite flag varieties, Lam, Lee, and Shimozono (2021) introduced bumpless pipe dreams in a new combinatorial formula for double Schubert polynomials. These polynomials are the TxT-equivariant cohomology classes of matrix Schubert varieties and of their flat degenerations. We give diagonal term orders with respect to which bumpless pipe dreams index the irreducible components of diagonal Gröbner degenerations of matrix Schubert varieties, counted with scheme-theoretic multiplicity. This indexing was conjectured by Hamaker, Pechenik, and Weigandt (2022). This result establishes that bumpless pipe dreams are dual to and as geometrically natural as classical pipe dreams, for which an analogous anti-diagonal theory was developed by Knutson and Miller (2005).
format Preprint
id arxiv_https___arxiv_org_abs_2108_08370
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Bumpless pipe dreams encode Gröbner geometry of Schubert polynomials
Klein, Patricia
Weigandt, Anna
Combinatorics
Commutative Algebra
Algebraic Geometry
14N15 (primary), 05E14, 13P10 (secondary)
In their study of infinite flag varieties, Lam, Lee, and Shimozono (2021) introduced bumpless pipe dreams in a new combinatorial formula for double Schubert polynomials. These polynomials are the TxT-equivariant cohomology classes of matrix Schubert varieties and of their flat degenerations. We give diagonal term orders with respect to which bumpless pipe dreams index the irreducible components of diagonal Gröbner degenerations of matrix Schubert varieties, counted with scheme-theoretic multiplicity. This indexing was conjectured by Hamaker, Pechenik, and Weigandt (2022). This result establishes that bumpless pipe dreams are dual to and as geometrically natural as classical pipe dreams, for which an analogous anti-diagonal theory was developed by Knutson and Miller (2005).
title Bumpless pipe dreams encode Gröbner geometry of Schubert polynomials
topic Combinatorics
Commutative Algebra
Algebraic Geometry
14N15 (primary), 05E14, 13P10 (secondary)
url https://arxiv.org/abs/2108.08370