2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/68109This paper is a contribution to Vinberg's theory of $θ$-groups, or in other words, to Invariant Theory of periodically graded semisimple Lie algebras. One of our main tools is Springer's theory of regular elements of finite reflection groups16 pagesAlgebraic Geometry14L30On Invarinat Theory of $θ$-groupstext