English

Classification of real trivectors in dimension nine

Representation Theory 2021-08-03 v1 Differential Geometry Group Theory Rings and Algebras

Abstract

We classify real trivectors in dimension 9. The corresponding classification over the field C of complex numbers was obtained by Vinberg and Elashvili in 1978. One of the main tools used for their classification was the construction of the representation of SL(9,C) on the space of complex trivectors of C^9 as a theta-representation corresponding to a Z/3Z-grading of the simple complex Lie algebra of type E_8. This divides the trivectors into three groups: nilpotent, semisimple, and mixed trivectors. Our classification follows the same pattern. We use Galois cohomology, first and second, to obtain the classification over R.

Cite

@article{arxiv.2108.00790,
  title  = {Classification of real trivectors in dimension nine},
  author = {Mikhail Borovoi and Willem A. de Graaf and Hông Vân Lê},
  journal= {arXiv preprint arXiv:2108.00790},
  year   = {2021}
}

Comments

Shortened version (submitted to a journal) of arXiv:2106.00246 [math.RT]; 38 pages

R2 v1 2026-06-24T04:44:54.906Z