- Speaker：Victor Petrov (S-Petersburg branch of Steklov Mathematical Institute of RAS)
- Organizer：Beijing-Moscow Mathematics Colloquium
- Start Time：2024-05-10 17:00
- End Time：2024-05-10 18:00
- Venue：online
Recording: https://disk.pku.edu.cn/link/AAD7E21F6CEA4C4545817349E93B9F70E1
Valid Until: 2054-05-10 18:40
Abstract: Simple Lie algebras over an algebraically closed field of characteristic 0 are described by Dynkin diagrams. Over a non-closed field, the same Dynkin diagram can correspond to many simple algebras, so it is interesting to study constructions of simple Lie algebras and invariants that make it possible to recognize their isomorphism or reflect some of their properties. One such construction of exceptional (i.e., types $E_6$, $E_7$, $E_8$, $F_4$ or $G_2$) Lie algebras was proposed by Jacques Tits; the Jordan algebra and an alternative algebra are given as input, and the output is a Lie algebra, and all real forms of Lie algebras can be constructed in this way. One of the most useful invariants (with meaning in the third Galois cohomology group) was constructed by Markus Rost. We show that a Lie algebra of (outer) type $E_6$ is obtained by the Tits construction if and only if the Rost invariant is a pure symbol. As an application of this result we prove a Springer-type theorem for an $E_6$-homogeneous manifold.
Bio: Viktor Petrov is a professor at St. Petersburg State University. He got his PhD degree in 2005 and Dr.Sci. degree in 2022, both from St. Petersburg State University. He was a postdoc at the University of Alberta (Edmonton, AB) and Max Planck Institute (Bonn, Germany). Viktor Petrov was awarded by the St. Petersburg Mathematical Society the prize for young mathematicians and won the "Young Russia Mathematics" contest (twice).
