Singular Degenerations of Lie Supergroups of Type D(2, 1; a)

The complex Lie superalgebras g of type D(2, 1; a) - also denoted by osp(4, 2; a) - are usually considered for "non-singular" values of the parameter a, for which they are simple. In this paper, we introduce five suitable integral forms of g that are well-defined at singular values too, gi...

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Опубліковано в: :Symmetry, Integrability and Geometry: Methods and Applications
Дата:2018
Автори: Iohara, K., Gavarini, F.
Формат: Стаття
Мова:English
Опубліковано: Інститут математики НАН України 2018
Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/209868
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:Singular Degenerations of Lie Supergroups of Type D(2, 1; a) / K. Iohara, F. Gavarini // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 18 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-209868
record_format dspace
spelling Iohara, K.
Gavarini, F.
2025-11-28T09:33:51Z
2018
Singular Degenerations of Lie Supergroups of Type D(2, 1; a) / K. Iohara, F. Gavarini // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 18 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 14A22; 17B20; 13D10
arXiv: 1709.04717
https://nasplib.isofts.kiev.ua/handle/123456789/209868
https://doi.org/10.3842/SIGMA.2018.137
The complex Lie superalgebras g of type D(2, 1; a) - also denoted by osp(4, 2; a) - are usually considered for "non-singular" values of the parameter a, for which they are simple. In this paper, we introduce five suitable integral forms of g that are well-defined at singular values too, giving rise to "singular specializations" that are no longer simple: this extends the family of simple objects of type D(2, 1; a) in five different ways. The resulting five families coincide for general values of a but are different at "singular" ones: here they provide non-simple Lie superalgebras, whose structure we describe explicitly. We also perform the parallel construction for complex Lie supergroups and describe their singular specializations (or "degenerations") at singular values of a. Although one may work with a single complex parameter a, in order to stress the overall S3-symmetry of the whole situation, we shall work (following Kaplansky) with a two-dimensional parameter σ=(σ₁,σ₂,σ₃) ranging in the complex affine plane σ₁+σ₂+σ₃=0.
The first author is partially supported by the French Agence Nationale de la Recherche (ANR GeoLie project ANR-15-CE40-0012). The second author acknowledges the MIUR Excellence Department Project awarded to the Department of Mathematics, University of Rome "Tor Vergata", CUP E83C18000100006. The authors would also like to thank the anonymous referees for their useful comments and suggestions to improve the presentation of this article.
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
spellingShingle Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
Iohara, K.
Gavarini, F.
title_short Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
title_full Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
title_fullStr Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
title_full_unstemmed Singular Degenerations of Lie Supergroups of Type D(2, 1; a)
title_sort singular degenerations of lie supergroups of type d(2, 1; a)
author Iohara, K.
Gavarini, F.
author_facet Iohara, K.
Gavarini, F.
publishDate 2018
language English
container_title Symmetry, Integrability and Geometry: Methods and Applications
publisher Інститут математики НАН України
format Article
description The complex Lie superalgebras g of type D(2, 1; a) - also denoted by osp(4, 2; a) - are usually considered for "non-singular" values of the parameter a, for which they are simple. In this paper, we introduce five suitable integral forms of g that are well-defined at singular values too, giving rise to "singular specializations" that are no longer simple: this extends the family of simple objects of type D(2, 1; a) in five different ways. The resulting five families coincide for general values of a but are different at "singular" ones: here they provide non-simple Lie superalgebras, whose structure we describe explicitly. We also perform the parallel construction for complex Lie supergroups and describe their singular specializations (or "degenerations") at singular values of a. Although one may work with a single complex parameter a, in order to stress the overall S3-symmetry of the whole situation, we shall work (following Kaplansky) with a two-dimensional parameter σ=(σ₁,σ₂,σ₃) ranging in the complex affine plane σ₁+σ₂+σ₃=0.
issn 1815-0659
url https://nasplib.isofts.kiev.ua/handle/123456789/209868
citation_txt Singular Degenerations of Lie Supergroups of Type D(2, 1; a) / K. Iohara, F. Gavarini // Symmetry, Integrability and Geometry: Methods and Applications. — 2018. — Т. 14. — Бібліогр.: 18 назв. — англ.
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