Bảo Châu NgôCollège de FranceFormes automorphes (chaire internationale)Année 2022-2023Théorie géométrique des représentationsSéminaire - Oscar Garcia-Prada : Vinberg Pairs and Higgs BundlesA finite order automorphism of a complex semisimple Lie group determines a cyclic grading of its Lie algebra. Vinberg's theory is concerned with the geometric invariant theory associated to this grading. Important examples include the case of involutions and representations of cyclic quivers. After reviewing some basic facts about Vinberg's theory, in this talk I will discuss about its relation to the geometry of moduli spaces of Higgs bundles over a compact Riemann surface.Oscar García-Prada is a CSIC Research Professor at Instituto de Ciencias Matemáticas— ICMAT, Madrid. He obtained a D.Phil. in Mathematics at the University of Oxford in 1991, and had postdoctoral appointments at Institut des Hautes Études Scientific (Paris), University of California at Berkeley, and University of Paris-Sud, before holding positions at University Autónoma of Madrid and École Polytéchnique (Paris). In 2002 he joined the Spanish National Research Council (CSIC).