Schmidt rank and singularities

UDC 512.5 We revisit Schmidt's theorem connecting the Schmidt rank of a tensor with the codimension of a certain variety and adapt the proof to the case of arbitrary characteristic. We also find a sharper result of this kind for homogeneous polynomials, assuming the characteris...

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Date:2023
Main Authors: Kazhdan, David, Lampert, Amichai, Polishchuk, Alexander
Format: Article
Language:English
Published: Institute of Mathematics, NAS of Ukraine 2023
Online Access:https://umj.imath.kiev.ua/index.php/umj/article/view/7227
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Journal Title:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
author_facet Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
author_sort Kazhdan, David
baseUrl_str https://umj.imath.kiev.ua/index.php/umj/oai
collection OJS
datestamp_date 2024-06-19T00:34:38Z
description UDC 512.5 We revisit Schmidt's theorem connecting the Schmidt rank of a tensor with the codimension of a certain variety and adapt the proof to the case of arbitrary characteristic. We also find a sharper result of this kind for homogeneous polynomials, assuming the characteristic does not divide the degree. Further, we use this to relate the Schmidt rank of a homogeneous polynomial (resp., a collection of homogeneous polynomials of the same degree) with the codimension of the singular locus of the corresponding hypersurface (resp., intersection of hypersurfaces). This gives an effective version of Ananyan--Hochster's theorem [J. Amer. Math. Soc., 33, No. 1, 291–309 (2020), Theorem A].
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spelling umjimathkievua-article-72272024-06-19T00:34:38Z Schmidt rank and singularities Schmidt rank and singularities Kazhdan, David Lampert, Amichai Polishchuk, Alexander Kazhdan, David Lampert, Amichai Polishchuk, Alexander Schmidt rank strength of a polynomial singular locus UDC 512.5 We revisit Schmidt's theorem connecting the Schmidt rank of a tensor with the codimension of a certain variety and adapt the proof to the case of arbitrary characteristic. We also find a sharper result of this kind for homogeneous polynomials, assuming the characteristic does not divide the degree. Further, we use this to relate the Schmidt rank of a homogeneous polynomial (resp., a collection of homogeneous polynomials of the same degree) with the codimension of the singular locus of the corresponding hypersurface (resp., intersection of hypersurfaces). This gives an effective version of Ananyan--Hochster's theorem [J. Amer. Math. Soc., 33, No. 1, 291–309 (2020), Theorem A]. УДК 512.5 Ранг Шмідта та сингулярності  Ми знову звертаємося до теореми Шмідта, яка пов'язує ранг Шмідта тензора з корозмірністю певного многовиду, і наводимо доведення, адаптоване до випадку довільної характеристики. Крім того, отримано більш точний результат такого роду для однорідних поліномів за припущення, що характеристика не є дільником степеня. Потім ми використовуємо цей факт, щоб зв’язати ранг Шмідта однорідного полінома (відповідно, колекції однорідних поліномів однакового степеня) з корозмірністю сингулярного локуса відповідної гіперповерхні (відповідно, перетину гіперповерхонь). Це дає ефективну версію теореми Ананяна–Хохстера [J. Amer. Math. Soc., 33, No. 1, 291–309 (2020), Theorem A] Institute of Mathematics, NAS of Ukraine 2023-09-26 Article Article https://umj.imath.kiev.ua/index.php/umj/article/view/7227 10.3842/umzh.v75i9.7227 Ukrains’kyi Matematychnyi Zhurnal; Vol. 75 No. 9 (2023); 1248 - 1266 Український математичний журнал; Том 75 № 9 (2023); 1248 - 1266 1027-3190 en https://umj.imath.kiev.ua/index.php/umj/article/view/7227/9749 Copyright (c) 2023 Alexander Polishchuk, David Kazhdan
spellingShingle Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
Kazhdan, David
Lampert, Amichai
Polishchuk, Alexander
Schmidt rank and singularities
title Schmidt rank and singularities
title_alt Schmidt rank and singularities
title_full Schmidt rank and singularities
title_fullStr Schmidt rank and singularities
title_full_unstemmed Schmidt rank and singularities
title_short Schmidt rank and singularities
title_sort schmidt rank and singularities
topic_facet Schmidt rank
strength of a polynomial
singular locus
url https://umj.imath.kiev.ua/index.php/umj/article/view/7227
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AT lampertamichai schmidtrankandsingularities
AT polishchukalexander schmidtrankandsingularities