Dept Math & Stat UiT, Forskningsparken B459
  20 Jan 2026 Wed 12:15-14:00

Andrea Santi (Rome Tor Vergata)

"Hyperplane arrangements and Vinberg's theta-groups"

Let g be a periodically graded semisimple complex Lie algebra. We give a uniform proof of the recent result by W.de Graaf and H.V.Le that the hyperplane arrangement determined by the restrictions of g-roots to a Cartan subspace c in g[1] coincides with the hyperplane arrangement of (complex) reflections of the little Weyl group of g. Joint work with Filippo Ambrosio.