Poset polytopes and pipe dreams: types C and B

Fuente: arXiv
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Main Authors: Makedonskyi, Ievgen, Makhlin, Igor
Format: Preprint
Published: 2024
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author Makedonskyi, Ievgen
Makhlin, Igor
author_facet Makedonskyi, Ievgen
Makhlin, Igor
contents 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 degenerations of flag varieties. All three families are parametrized by the same family of polytopes: the marked chain-order polytopes of Fang and Fourier which interpolate between the type C Gelfand--Tsetlin and FFLV polytopes. Thus, in each case the obtained structures interpolate between the well-known bases, Newton--Okounkov bodies or degenerations associated with the latter two polytopes. We then obtain similar results for type B after introducing a new family of poset polytopes to be considered in place of marked chain-order polytopes. In both types our constructions and proofs rely crucially on a combinatorial connection between poset polytopes and pipe dreams.
format Preprint
id arxiv_https___arxiv_org_abs_2402_16207
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Poset polytopes and pipe dreams: types C and B
Makedonskyi, Ievgen
Makhlin, Igor
Representation Theory
Algebraic Geometry
Combinatorics
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 degenerations of flag varieties. All three families are parametrized by the same family of polytopes: the marked chain-order polytopes of Fang and Fourier which interpolate between the type C Gelfand--Tsetlin and FFLV polytopes. Thus, in each case the obtained structures interpolate between the well-known bases, Newton--Okounkov bodies or degenerations associated with the latter two polytopes. We then obtain similar results for type B after introducing a new family of poset polytopes to be considered in place of marked chain-order polytopes. In both types our constructions and proofs rely crucially on a combinatorial connection between poset polytopes and pipe dreams.
title Poset polytopes and pipe dreams: types C and B
topic Representation Theory
Algebraic Geometry
Combinatorics
url https://arxiv.org/abs/2402.16207