{ "id": "2212.03775", "version": "v1", "published": "2022-12-07T16:47:11.000Z", "updated": "2022-12-07T16:47:11.000Z", "title": "Semisimple elements and the little Weyl group of real semisimple $Z_m$-graded Lie algebras", "authors": [ "Willem de Graaf", "Hông Vân Lê" ], "comment": "Preliminary version, 18 p. Comments welcome! arXiv admin note: substantial text overlap with arXiv:2106.00246", "categories": [ "math.RT", "math.DG", "math.GR", "math.RA" ], "abstract": "In this paper we introduce the notion of the algebraic $\\theta$-group of a semisimple $Z_m$-graded Lie algebra over a field $k$ of characteristic $0$ whose identity component is the $\\theta$-group. Using this, we extend a number of results concerning structure of semisimple elements in complex semisimple $Z_m$-graded Lie algebras and some results concerning real (and complex) semisimple Lie algebras to the case of real (and complex) semisimple $Z_m$-graded Lie algebras, using Galois cohomology theory and ad hoc techniques. In particular, we parameterize the conjugacy classes of Cartan subspaces in a real semisimple $Z_m$-graded Lie algebra $g$ in terms of Galois cohomology. We prove that if $m$ is a prime number or $g^c$ is a complex semisimple $Z_m$-graded Lie algebra of maximal rank then the centralizer $Z_{g^c}(p)$ of a homogeneous semisimple element $p$ and the stabilizer $W_p$ of $p$ under the Weyl group action define each other. As a result, we obtain a number of consequences on the conjugacy classes of homogeneous semisimple elements in $g^c$ and in its real forms.", "revisions": [ { "version": "v1", "updated": "2022-12-07T16:47:11.000Z" } ], "analyses": { "subjects": [ "11E72", "20G05", "20G20" ], "keywords": [ "graded lie algebra", "little weyl group", "real semisimple", "homogeneous semisimple element", "complex semisimple" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }