Singularities of Schubert Varieties within a Right Cell

We describe an algorithm that pattern embeds, in the sense of Woo-Yong, any Bruhat interval of a symmetric group into an interval whose extremes lie in the same right Kazhdan-Lusztig cell. This apparently harmless fact has applications in finding examples of reducible associated varieties of ₙ-high...

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Published in:Symmetry, Integrability and Geometry: Methods and Applications
Date:2021
Main Authors: Lanini, Martina, McNamara, Peter J.
Format: Article
Language:English
Published: Інститут математики НАН України 2021
Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/211353
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Singularities of Schubert Varieties within a Right Cell. Martina Lanini and Peter J. McNamara. SIGMA 17 (2021), 070, 9 pages

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Summary:We describe an algorithm that pattern embeds, in the sense of Woo-Yong, any Bruhat interval of a symmetric group into an interval whose extremes lie in the same right Kazhdan-Lusztig cell. This apparently harmless fact has applications in finding examples of reducible associated varieties of ₙ-highest weight modules, as well as in the study of W-graphs for symmetric groups, and in comparing various bases of irreducible representations of the symmetric group or its Hecke algebra. For example, we can systematically produce many negative answers to a question from the 1980s of Borho-Brylinski and Joseph, which had been settled by Williamson via computer calculations only in 2014.
ISSN:1815-0659