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Related papers: Embedding bumpless pipedreams as Bruhat chains

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Lascoux and Sch\"utzenberger introduced Schubert and Grothendieck polynomials to study the cohomology and K-theory of the complete flag variety. We present explicit combinatorial rules for expressing Grothendieck polynomials in the basis of…

Combinatorics · Mathematics 2025-06-10 Anna Weigandt

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…

Combinatorics · Mathematics 2025-09-03 Patricia Klein , Anna Weigandt

Bumpless pipe dreams (BPDs) are combinatorial objects used in the study of Schubert and Grothendieck polynomials. Weigandt recently introduced a co-BPD object associated to each BPD and used them to give an analogue to the change of bases…

Combinatorics · Mathematics 2026-01-01 Joshua Arroyo , Adam Gregory

Schubert polynomials are polynomial representatives of Schubert classes in the cohomology of the complete flag variety and have a combinatorial formulation in terms of bumpless pipe dreams. Quantum double Schubert polynomials are polynomial…

Combinatorics · Mathematics 2025-02-12 Tuong Le , Shuge Ouyang , Leo Tao , Joseph Restivo , Angelina Zhang

We introduce analogs of left and right RSK insertion for Schubert calculus of complete flag varieties. The objects being inserted are certain biwords, the insertion objects are bumpless pipe dreams, and the recording objects are decorated…

Combinatorics · Mathematics 2022-06-30 Daoji Huang , Pavlo Pylyavskyy

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

Involution Schubert polynomials represent cohomology classes of $K$-orbit closures in the complete flag variety, where $K$ is the orthogonal or symplectic group. We show they also represent $T$-equivariant cohomology classes of subvarieties…

Combinatorics · Mathematics 2022-11-09 Zachary Hamaker , Eric Marberg , Brendan Pawlowski

Schubert polynomials represent a basis for the cohomology of the complete flag variety and thus play a central role in geometry and combinatorics. In this context, Schubert polynomials are generating functions over various combinatorial…

Combinatorics · Mathematics 2025-01-30 Sarah Gold , Elizabeth Milićević , Yuxuan Sun

We define skew Schubert polynomials to be normal form (polynomial) representatives of certain classes in the cohomology of a flag manifold. We show that this definition extends a recent construction of Schubert polynomials due to Bergeron…

Combinatorics · Mathematics 2010-03-29 Cristian Lenart , Frank Sottile

Pipedreams and bumpless pipedreams are two combinatorial models that compute double Grothendieck polynomials. While studying matrix Schubert varieties, Pechenik, Speyer, and Weigandt defined a permutation statistic$\mathsf{rajcode}(\cdot)$…

Combinatorics · Mathematics 2026-05-26 Xuanying Han , Sophie C. C. Sun

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

We study a family of polynomials whose values express degrees of Schubert varieties in the generalized complex flag manifold G/B. The polynomials are given by weighted sums over saturated chains in the Bruhat order. We derive several…

Combinatorics · Mathematics 2007-05-23 Alexander Postnikov , Richard P. Stanley

We illuminate the relation between the Bruhat order on the symmetric group and structure constants (Littlewood-Richardson coefficients) for the cohomology of the flag manifold in terms of its basis of Schubert classes. Equivalently, the…

alg-geom · Mathematics 2016-11-08 Nantel Bergeron , Frank Sottile

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

We construct a bijection between marked bumpless pipedreams with reverse compatible pairs, which are in bijection with not-necessarily-reduced pipedreams. This directly unifies various formulas for Grothendieck polynomials in the…

Combinatorics · Mathematics 2024-07-26 Daoji Huang , Mark Shimozono , Tianyi Yu

We give bijective proofs of Monk's rule for Schubert and double Schubert polynomials computed with bumpless pipe dreams. In particular, they specialize to bijective proofs of transition and cotransition formulas of Schubert and double…

Combinatorics · Mathematics 2020-10-29 Daoji Huang

Knutson and Zinn-Justin recently found a puzzle rule for the expansion of the product $\mathfrak{G}_{u}(x,t)\cdot \mathfrak{G}_{v}(x,t)$ of two double Grothendieck polynomials indexed by permutations with separated descents. We establish…

Combinatorics · Mathematics 2025-10-15 Neil J. Y. Fan , Peter L. Guo , Rui Xiong

The quantum Bruhat graph, which is an extension of the graph formed by covering relations in the Bruhat order, is naturally related to the quantum cohomology ring of G/B. We enhance a result of Fulton and Woodward by showing that the…

Combinatorics · Mathematics 2007-05-23 Alexander Postnikov

Weighted enumeration of reduced pipe dreams (or rc-graphs) results in a combinatorial expression for Schubert polynomials. The duality between the set of reduced pipe dreams and certain antidiagonals has important geometric implications [A.…

Combinatorics · Mathematics 2008-05-27 Ning Jia , Ezra Miller

In [KU23] were introduced hybrid pipe dreams interpolating between classic and bumpless pipe dreams, each hybridization giving a different formula for double Schubert polynomials. A bijective proof was given (following [GH23]) of the…

Combinatorics · Mathematics 2025-09-03 Allen Knutson , Paul Zinn-Justin
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