Regular extreme semisimple Lie algebras

Seminario del Dipartimento di Matematica
23 May 2024
Start time 
4:00 pm
Polo Ferrari 1 - Via Sommarive 5, Povo (Trento)
Aula A218
Dipartimento di Matematica
Target audience: 
University community
UniTrento students
Contact person: 
Prof. Willem Adriaan De Graaf, dott.ssa Mima Stanojkovski
Contact details: 
Staff Dipartimento di Matematica
Andrew Douglas (City University of New York)


A subalgebra of a semisimple Lie algebra is wide if every simple module of the semisimple Lie algebra remains indecomposable when restricted to the ubalgebra. A subalgebra is narrow if the restrictions of all non-trivial simple modules to the subalgebra have proper decompositions. A semisimple Lie algebra is regular extreme if any regular subalgebra of the semisimple Lie algebra is either narrow or wide. In this talk, I'll present our recent work showing that all simple Lie algebras are regular extreme; and that no non-simple, semisimple Lie algebra is regular extreme. Note that all Lie algebras and modules in this talk are finite-dimensional and over the complex numbers.