Hilbert series of the Grassmannian and k-Narayana numbers

We compute the Hilbert series of the complex Grassmannian using invariant theoretic methods. This is made possible by showing that the denominator of the q-Hilbert series is a Vandermonde-like determinant. We show that the h-polynomial of the Grassmannian coincides with the k-Narayana polynomial. A...

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Main Author: Braun Lukas
Format: Article
Language:English
Published: Sciendo 2019-06-01
Series:Communications in Mathematics
Subjects:
Online Access:https://doi.org/10.2478/cm-2019-0003
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spelling doaj-333a9dc87c59432fb6391719410f65f12021-09-06T19:22:06ZengSciendoCommunications in Mathematics2336-12982019-06-01271274110.2478/cm-2019-0003cm-2019-0003Hilbert series of the Grassmannian and k-Narayana numbersBraun Lukas0Mathematisches Institut, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, GermanyWe compute the Hilbert series of the complex Grassmannian using invariant theoretic methods. This is made possible by showing that the denominator of the q-Hilbert series is a Vandermonde-like determinant. We show that the h-polynomial of the Grassmannian coincides with the k-Narayana polynomial. A simplified formula for the h-polynomial of Schubert varieties is given. Finally, we use a generalized hypergeometric Euler transform to find simplified formulae for the k-Narayana numbers, i.e. the h-polynomial of the Grassmannian.https://doi.org/10.2478/cm-2019-0003hilbert series of the grassmanniannarayana numberseuler’s hypergeometric transform14m1513d4033c90
collection DOAJ
language English
format Article
sources DOAJ
author Braun Lukas
spellingShingle Braun Lukas
Hilbert series of the Grassmannian and k-Narayana numbers
Communications in Mathematics
hilbert series of the grassmannian
narayana numbers
euler’s hypergeometric transform
14m15
13d40
33c90
author_facet Braun Lukas
author_sort Braun Lukas
title Hilbert series of the Grassmannian and k-Narayana numbers
title_short Hilbert series of the Grassmannian and k-Narayana numbers
title_full Hilbert series of the Grassmannian and k-Narayana numbers
title_fullStr Hilbert series of the Grassmannian and k-Narayana numbers
title_full_unstemmed Hilbert series of the Grassmannian and k-Narayana numbers
title_sort hilbert series of the grassmannian and k-narayana numbers
publisher Sciendo
series Communications in Mathematics
issn 2336-1298
publishDate 2019-06-01
description We compute the Hilbert series of the complex Grassmannian using invariant theoretic methods. This is made possible by showing that the denominator of the q-Hilbert series is a Vandermonde-like determinant. We show that the h-polynomial of the Grassmannian coincides with the k-Narayana polynomial. A simplified formula for the h-polynomial of Schubert varieties is given. Finally, we use a generalized hypergeometric Euler transform to find simplified formulae for the k-Narayana numbers, i.e. the h-polynomial of the Grassmannian.
topic hilbert series of the grassmannian
narayana numbers
euler’s hypergeometric transform
14m15
13d40
33c90
url https://doi.org/10.2478/cm-2019-0003
work_keys_str_mv AT braunlukas hilbertseriesofthegrassmannianandknarayananumbers
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