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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

The geometric naturality of Schubert polynomials and their combinatorial pipe dream representations was established by Knutson and Miller (2005) via antidiagonal Gr\"obner degeneration of matrix Schubert varieties. We consider instead…

Combinatorics · Mathematics 2022-03-25 Zachary Hamaker , Oliver Pechenik , Anna Weigandt

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…

Combinatorics · Mathematics 2025-11-25 Yiming Chen , Neil J. Y. Fan , Rui Xiong , Ming Yao

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

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

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 develop a family of new combinatorial models for key polynomials. It is similar to the hybrid pipe dream model for Schubert polynomials defined recently by Knutson and Udell.

Combinatorics · Mathematics 2025-10-15 Yihan Xiao , Rui Xiong , Haofeng Zhang

Two well-known polytopes whose vertices are indexed by permutations in the symmetric group $\mathfrak{S}_n$ are the permutohedron $P_n$ and the Birkhoff polytope $B_n$. We consider polytopes $P_n(\Pi)$ and $B_n(\Pi)$, whose vertices…

Combinatorics · Mathematics 2018-07-18 Robert Davis , Bruce Sagan

We characterize totally symmetric self-complementary plane partitions (TSSCPP) as bounded compatible sequences satisfying a Yamanouchi-like condition. As such, they are in bijection with certain pipe dreams. Using this characterization and…

Combinatorics · Mathematics 2024-02-06 Daoji Huang , Jessica Striker

Lam, Lee and Shimozono introduced the structure of bumpless pipedreams in their study of back stable Schubert calculus. They found that a specific family of bumpless pipedreams, called EG-pipedreams, can be used to interpret the…

Combinatorics · Mathematics 2018-10-30 Neil J. Y. Fan , Peter L. Guo , Sophie C. C. Sun

A permutation is called covexillary if it avoids the pattern $3412$. We construct an open embedding of a covexillary matrix Schubert variety into a Grassmannian Schubert variety. As applications of this embedding, we show that the…

Algebraic Geometry · Mathematics 2022-03-29 Rahul Singh

Bidirectional transformations (bx) have primarily been modeled as pure functions, and do not account for the possibility of the side-effects that are available in most programming languages. Recently several formulations of bx that use…

Programming Languages · Computer Science 2017-09-12 Faris Abou-Saleh , James Cheney , Jeremy Gibbons , James McKinna , Perdita Stevens

We give a new proof that three families of polynomials coincide: the double Schubert polynomials of Lascoux and Sch\"utzenberger defined by divided difference operators, the pipe dream polynomials of Bergeron and Billey, and the equivariant…

Combinatorics · Mathematics 2022-02-08 Allen Knutson

Pipedreams are combinatorial objects that compute Grothendieck polynomials. We introduce a new combinatorial object that naturally recast the pipedream formula. From this, we obtain the first direct combinatorial formula for the top degree…

Combinatorics · Mathematics 2025-02-12 Chen-An Chou , Tianyi Yu

In this paper, we are interested in the combinatorial analysis of the whole genome duplication - random loss model of genome rearrangement initiated in a paper of Chaudhuri, Chen, Mihaescu, and Rao in SODA 2006 and continued by Bouvel and…

Combinatorics · Mathematics 2008-12-18 Mathilde Bouvel , Elisa Pergola

We construct and analyze several new families of permutons arising from random processes involving the Demazure product on the symmetric group. First, we consider Demazure products associated to random pipe dreams, generalizing the…

Probability · Mathematics 2025-05-22 Colin Defant

We characterize separable multidimensional permutations in terms of forbidden patterns and enumerate them by means of generating function, recursive formula and explicit formula. We find a connection between multidimensional permutations…

Combinatorics · Mathematics 2008-03-25 Andrei Asinowski , Toufik Mansour

A bilevel program is an optimization problem whose constraints involve another optimization problem. This paper studies bilevel polynomial programs (BPPs), i.e., all the functions are polynomials. We reformulate BPPs equivalently as…

Optimization and Control · Mathematics 2016-11-04 Jiawang Nie , Li Wang , Jane Ye

This paper puts forward a new generalized polynomial dimensional decomposition (PDD), referred to as GPDD, comprising hierarchically ordered measure-consistent multivariate orthogonal polynomials in dependent random variables. Unlike the…

Numerical Analysis · Mathematics 2018-10-30 Sharif Rahman

Kazhdan-Lusztig ideals, a family of generalized determinantal ideals investigated in [Woo-Yong '08], provide an explicit choice of coordinates and equations encoding a neighbourhood of a torus-fixed point of a Schubert variety on a type A…

Combinatorics · Mathematics 2012-07-31 Alexander Woo , Alexander Yong