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Related papers: Poset polytopes and pipe dreams: toric degeneratio…

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The first part of this paper concerns type C. We present new explicitly defined families of algebro-combinatorial structures of three kinds: combinatorial bases in representations, Newton--Okounkov bodies of flag varieties and toric…

Representation Theory · Mathematics 2025-07-29 Ievgen Makedonskyi , Igor Makhlin

Our first result realizes the toric variety of every marked chain-order polytope (MCOP) of the Gelfand--Tsetlin poset as an explicit Gr\"obner (sagbi) degeneration of the flag variety. This generalizes the…

Algebraic Geometry · Mathematics 2024-06-28 Igor Makhlin

We study toric degenerations arising from Gr\"obner degenerations or the tropicalization of partial flag varieties. We produce a new family of toric degenerations of partial flag varieties whose combinatorics are governed by matching fields…

Algebraic Geometry · Mathematics 2023-10-12 Oliver Clarke , Fatemeh Mohammadi , Francesca Zaffalon

Following the historical track in pursuing $T$-equivariant flat toric degenerations of flag varieties and spherical varieties, we explain how powerful tools in algebraic geometry and representation theory, such as canonical bases,…

Algebraic Geometry · Mathematics 2016-09-06 Xin Fang , Ghislain Fourier , Peter Littelmann

In this thesis we study toric degenerations of projective varieties. We compare different constructions to understand how and why they are related as s first step towards developing a global framework. In focus are toric degenerations…

Algebraic Geometry · Mathematics 2018-06-07 Lara Bossinger

Marked chain-order polytopes are convex polytopes constructed from a marked poset, which give a discrete family relating a marked order polytope with a marked chain polytope. In this paper, we consider the Gelfand-Tsetlin poset of type A,…

Algebraic Geometry · Mathematics 2021-04-21 Naoki Fujita

This note constructs the flat toric degeneration of the manifold FL_n of flags in C^n from [Gonciulea-Lakshmibai 96] as an explicit GIT quotient of the Gr"obner degeneration in [Knutson-Miller 03]. This implies that Schubert varieties…

Algebraic Geometry · Mathematics 2007-05-23 Mikhail Kogan , Ezra Miller

The two best studied toric degenerations of the flag variety are those given by the Gelfand--Tsetlin and FFLV polytopes. Each of them degenerates further into a particular monomial variety which raises the problem of describing the…

Algebraic Geometry · Mathematics 2024-02-28 Evgeny Feigin , Igor Makhlin

In this survey I summarize the constructions of toric degenerations obtained from valuations and Gr\"obner theory and describe in which sense they are equivalent. I show how adapted bases can be used to generalize the classical Newton…

Algebraic Geometry · Mathematics 2023-01-09 Lara Bossinger

The main result of this note is that the toric degenerations of flag varieties associated to string polytopes and certain Bott-Samelson resolutions of flag varieties fit into a commutative diagram which gives a resolution of singularities…

Algebraic Geometry · Mathematics 2017-12-29 Megumi Harada , Jihyeon Jessie Yang

Let $X$ be a smooth irreducible complex algebraic variety of dimension $n$ and $L$ a very ample line bundle on $X$. Given a toric degeneration of $(X,L)$ satisfying some natural technical hypotheses, we construct a deformation $\{J_s\}$ of…

Symplectic Geometry · Mathematics 2018-03-02 Mark Hamilton , Megumi Harada , Kiumars Kaveh

In this paper we show that the pipe dream complex associated to the permutation 1n(n-1)...2 can be geometrically realized as a triangulation of the vertex figure of a root polytope. Leading up to this result we show that the Grothendieck…

Combinatorics · Mathematics 2015-11-02 Karola Mészáros

The theory of polyptych lattices is a framework to obtain a family of toric degenerations whose polytopes are related by piecewise-linear transformations. It can be regarded as a generalization of toric degenerations arising from cluster…

Algebraic Geometry · Mathematics 2026-03-24 Naoki Fujita , Akihiro Higashitani

We show that a weight variety, which is a quotient of a flag variety by the maximal torus, admits a flat degeneration to a toric variety. In particular, we show that the moduli spaces of spatial polygons degenerate to polarized toric…

Algebraic Geometry · Mathematics 2007-05-23 Philip Foth , Yi Hu

Given a smooth Mori dream space $X$ we construct a model dominating all the small $\mathbb{Q}$-factorial modifications via tropicalization. This construction allows us to recover a Minkowski basis for the Newton-Okounkov bodies of divisors…

Algebraic Geometry · Mathematics 2018-01-26 Elisa Postinghel , Stefano Urbinati

The goal of this paper is to study the link between the topology of the degenerate flag varieties and combinatorics of the Dellac configurations. We define three new classes of algebraic varieties closely related to the degenerate flag…

Combinatorics · Mathematics 2018-08-14 Ange Bigeni , Evgeny Feigin

We classify projective toric manifolds whose dual variety is not a hypersurface in the dual projective space. Under the standard dictionary between toric geometry and convex geometry, they correspond to certain convex Delzant integer…

Algebraic Geometry · Mathematics 2007-05-23 Sandra Di Rocco

A toric degeneration of an irreducible variety is a flat degeneration to an irreducible toric variety. In the case of a flag variety, its toric degeneration with desirable properties induces degenerations of Richardson varieties to unions…

Algebraic Geometry · Mathematics 2025-07-24 Naoki Fujita

We present a new approach to construct $T$-equivariant flat toric degenerations of flag varieties and spherical varieties, combining ideas coming from the theory of Newton-Okounkov bodies with ideas originally stemming from PBW-filtrations.…

Algebraic Geometry · Mathematics 2017-10-03 Xin Fang , Ghislain Fourier , Peter Littelmann

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
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