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Let G be a simple algebraic group over an algebraically closed field with Lie algebra g. Then the orbits of nilpotent elements of g under the adjoint action of G have been classified. We describe a simple algorithm for finding a…

Group Theory · Mathematics 2011-11-09 Willem de Graaf

We report on some computations with nilpotent orbits in simple Lie algebras of exceptional type within the SLA package of GAP4. Concerning reachable nilpotent orbits our computations firstly confirm the classification of such orbits in Lie…

Rings and Algebras · Mathematics 2013-01-08 Willem A. de Graaf

The main part of this paper contains a description of a nilpotent quotient algorithm for L-presented groups and a report on applications of its implementation in the computer algebra system GAP. The appendix introduces two new infinite…

Group Theory · Mathematics 2009-11-27 Bettina Eick , René Hartung , Laurent Bartholdi

The theory of nilpotent orbits of simple Lie algebras has seen tremendous developments over the past decades. In this context an important role is played by the component group of the stabilizer of a nilpotent element. In this work, the aim…

Representation Theory · Mathematics 2024-07-17 Emanuele Di Bella , Willem A. De Graaf

Let g be a real form of a simple complex Lie algebra. Based on ideas of Djokovic and Vinberg, we describe an algorithm to compute representatives of the nilpotent orbits of g using the Kostant-Sekiguchi correspondence. Our algorithms are…

Rings and Algebras · Mathematics 2012-09-26 Heiko Dietrich , Willem A. de Graaf

A systematic way to organise the interesting periods of automorphic forms on a reductive group $G$ is via the theory of nilpotent orbits of $G$. On the other hand, it is known that the theta correspondence can be used effectively to relate…

Number Theory · Mathematics 2025-07-28 Bryan Wang Peng Jun

We describe algorithms for computing the induced nilpotent orbits in semisimple Lie algebras. We use them to obtain the induction tables for the Lie algebras of exceptional type. This also yields the classification of the rigid nilpotent…

Representation Theory · Mathematics 2009-07-09 W. A. de Graaf , A. G. Elashvili

We survey group-theoretic algorithms for finding (some or all) subgroups of a finite group and discuss the implementation of these algorithms in the computer algebra system GAP

Group Theory · Mathematics 2020-12-04 Alexander Hulpke

We compute special unipotent Arthur packets for real reductive groups in many cases. We list the cases that lead to incomplete answers, and in those cases, provide a suitable set of representations that could lead to a complete description…

Representation Theory · Mathematics 2018-11-16 Jonathan Fernandes

We develop methods for computing with matrix groups defined over a range of infinite domains, and apply those methods to the design of algorithms for nilpotent groups. In particular, we provide a practical algorithm to test nilpotency of…

Group Theory · Mathematics 2019-07-16 A. S. Detinko , D. L. Flannery

We develop an algorithm for computing the closure of a given nilpotent $G_0$-orbit in $\g_1$, where $\g_1$ and $G_0$ are coming from a $\Z$ or a $\Z/m\Z$-grading $\g= \bigoplus \g_i$ of a simple complex Lie algebra $\g$.

Algebraic Geometry · Mathematics 2015-03-19 W. A. de Graaf , E. B. Vinberg , O. S. Yakimova

Building on our previous work (arXiv:1405.5711), we develop the first practical algorithm for computing topological zeta functions of nilpotent groups, non-associative algebras, and modules. While we previously depended upon non-degeneracy…

Group Theory · Mathematics 2014-09-18 Tobias Rossmann

We illustrate the Lie theoretic capabilities of the computational algebra system GAP4 by reporting on results on nilpotent orbits of simple Lie algebras that have been obtained using computations in that system. Concerning reachable…

Representation Theory · Mathematics 2023-03-29 Willem A. de Graaf

First, I construct an isomorphism between the categories of (topological) groups of nilpotency class 2 with 2-divisible center and (topological) Lie rings of nilpotency class 2 with 2-divisible center. That isomorphism allows us to…

Representation Theory · Mathematics 2007-05-23 Aleksandrs Mihailovs

Let $G$ be a simple algebraic group over an algebraically closed field $k$ of characteristic $p$. The classification of the conjugacy classes of unipotent elements of $G(k)$ and nilpotent orbits of $G$ on $\operatorname{Lie}(G)$ is…

Group Theory · Mathematics 2023-03-22 Mikko Korhonen , David I. Stewart , Adam R. Thomas

A linear \'etale representation of a complex algebraic group $G$ is given by a complex algebraic $G$-module $V$ such that $G$ has a Zariski-open orbit on $V$ and $\dim G=\dim V$. A current line of research investigates which \'etale…

Representation Theory · Mathematics 2021-03-01 Heiko Dietrich , Wolfgang Globke , Marcos Origlia

We compute the representation zeta functions of some finitely generated nilpotent groups associated to unipotent group schemes over rings of integers in number fields. These group schemes are defined by Lie lattices whose presentations are…

Group Theory · Mathematics 2016-05-25 Alexander Stasinski , Christopher Voll

Let $G$ be a real simple Lie group, $\got g$ its Lie algebra. Given a nilpotent adjoint $G$-orbit $O$, the question is to determine the irreducible unitary representations of $G$ that we can associate to $O$, according to the orbit method.…

Representation Theory · Mathematics 2007-05-23 Hervé Sabourin

For a semisimple Lie algebra over the complex numbers, Dynkin (1952) developed an algorithm to classify the regular semisimple subalgebras, up to conjugacy by the inner automorphism group. For a graded semisimple Lie algebra over the…

Representation Theory · Mathematics 2014-07-30 H. Dietrich , Paolo Faccin , Willem A. de Graaf

We develop techniques for computing zeta functions associated with nilpotent groups, not necessarily associative algebras, and modules, as well as Igusa-type zeta functions. At the heart of our method lies an explicit convex-geometric…

Group Theory · Mathematics 2014-05-23 Tobias Rossmann
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