Levy, Paul (2007) *Varieties of modules for Z/2Z×Z/2Z.* Journal of Algebra, 318 (2). pp. 933-952. ISSN 0021-8693

## Abstract

Let k be an algebraically closed field of characteristic 2. We prove that the restricted nilpotent commuting variety C, that is the set of pairs of (n×n)-matrices (A,B) such that A2=B2=[A,B]=0, is equidimensional. C can be identified with the ‘variety of n-dimensional modules’ for Z/2Z×Z/2Z, or equivalently, for k[X,Y]/(X2,Y2). On the other hand, we provide an example showing that the restricted nilpotent commuting variety is not equidimensional for fields of characteristic >2. We also prove that if e2=0 then the set of elements of the centralizer of e whose square is zero is equidimensional. Finally, we express each irreducible component of C as a direct sum of indecomposable components of varieties of Z/2Z×Z/2Z-modules.

Item Type: | Article |
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Journal or Publication Title: | Journal of Algebra |

Uncontrolled Keywords: | Lie algebras in positive characteristic |

Subjects: | |

Departments: | Faculty of Science and Technology > Mathematics and Statistics |

ID Code: | 51957 |

Deposited By: | ep_importer_pure |

Deposited On: | 09 Dec 2011 13:23 |

Refereed?: | Yes |

Published?: | Published |

Last Modified: | 04 Apr 2016 01:16 |

Identification Number: | |

URI: | http://eprints.lancs.ac.uk/id/eprint/51957 |

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