{ "id": "0905.0065", "version": "v3", "published": "2009-05-01T08:50:25.000Z", "updated": "2010-06-29T10:01:47.000Z", "title": "Complete Reducibility and Conjugacy classes of tuples in Algebraic Groups and Lie algebras", "authors": [ "M. Bate", "B. Martin", "G. Roehrle", "R. Tange" ], "comment": "23 pages; final version to appear in Math. Z; various changes following suggestion by the referee", "categories": [ "math.GR", "math.RT" ], "abstract": "Let H be a reductive subgroup of a reductive group G over an algebraically closed field k. We consider the action of H on G^n, the n-fold Cartesian product of G with itself, by simultaneous conjugation. We give a purely algebraic characterization of the closed H-orbits in G^n, generalizing work of Richardson which treats the case H = G. This characterization turns out to be a natural generalization of Serre's notion of G-complete reducibility. This concept appears to be new, even in characteristic zero. We discuss how to extend some key results on G-complete reducibility in this framework. We also consider some rationality questions.", "revisions": [ { "version": "v3", "updated": "2010-06-29T10:01:47.000Z" } ], "analyses": { "subjects": [ "20G15", "14L24", "20E42" ], "keywords": [ "algebraic groups", "conjugacy classes", "lie algebras", "g-complete reducibility", "n-fold cartesian product" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0905.0065B" } } }