Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-28T12:36:58.240Z Has data issue: false hasContentIssue false

Nilpotent orbits of exceptional Lie algebras over algebraically closed fields of bad characteristic

Published online by Cambridge University Press:  09 April 2009

D. F. Holt
Affiliation:
Mathematics Institute University of WarwickCoventry, England
N. Spaltenstein
Affiliation:
Mathamatisches Institut der Universität BernSidlerstrasse 5 3012 Bern, Switzerland
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The classification of the nilpotent orbits in the Lie algebra of a reductive algebraic group (over an algebraically closed field) is given in all the cases where it was not previously known (E7 and E8 in bad characteristic, F4 in characteristic 3). The paper exploits the tight relation with the corresponding situation over a finite field. A computer is used to study this case for suitable choices of the finite field.

Type
Research Article
Copyright
Copyright © Australian Mathematical Society 1985

References

[1]Alvis, D. and Lusztig, G., ‘On Springer's correspondence for simple groups of type En (n = 6,7,8)’, Math. Proc. Cambridge Phil. Soc. 92 (1982), 6578.CrossRefGoogle Scholar
[2]Baja, P. and Carter, R. W., ‘Classes of unipotent elements in simple algebraic groups’, Math. Proc. Cambridge Philos. Soc. 79 (1976), 401425; 80 (1976), 1–18.Google Scholar
[3]Borho, W. and MacPherson, R., ‘Representations des groupes de Weyl et homologie d'intersection pour les variétés nilpotentes’, C. R. Acad. Sci. Paris Sér. I Math. 292 (1981), n° 15, 707710.Google Scholar
[4]Bourbaki, N., Groupes et algebres de Lie, chap. IV, V, VI (Paris, Hermann, 1968).Google Scholar
[5]Hesselink, W. H., ‘Nilpotency in classical groups over a field of characteristic 2’, Math. Z. 166 (1979), 165181.CrossRefGoogle Scholar
[6]Felsch, V. and Neubüser, J., ‘An algorithm for the computation of conjugacy classes and centralizers in p-groups’, Symbolic and algebraic computation, Edited by Ng, E. W. K. (Lecture Notes in Computer Science 72, Berlin-Heidelberg-New York, Springer-Verlag, 1979). pp. 452456.CrossRefGoogle Scholar
[7]Jeurissen, R. H., The automorphism groups of octave algebras (Doctoral dissertation, University of Utrecht).Google Scholar
[8]Lusztig, G., ‘On the finiteness of the number of unipotent classes’, Invent. Math. 34 (1976), 201213.CrossRefGoogle Scholar
[9]Lusztig, G., ‘Green polynomials and singularities of unipotent classes’, Advances in Math. 42 (1981), 169178.CrossRefGoogle Scholar
[10]Lusztig, G. and Spaltenstein, N., ‘Induced unipotent classes’, J. London Math. Soc. 19 (1979), 4152.CrossRefGoogle Scholar
[11]Mizuno, K., ‘The conjugate classes of Chevalley groups of type E6’, J. Fac. Sci. Univ. Tokyo Sec. 1A Math. 24 (1977), 525563.Google Scholar
[12]Mizuno, K., ‘The conjugate classes of unipotent elements of the Chevalley groups E7 and E8’, Tokyo J. Math. 3 (1980), 391461.CrossRefGoogle Scholar
[13]Shoji, T., ‘The conjugate classes of Chevalley groups of type (F4) over finite fields of characteristic p ≠ 2’, J. Fac. Sci. Univ. Tokyo Sec. 1A Math. 21 (1974), 117.Google Scholar
[14]Spaltenstein, N., ‘On the fixed point set of a unipotent element on the variety of Borel subgroups’, Topology 16 (1977), 203204.CrossRefGoogle Scholar
[15]Spaltenstein, N., Classes unipotentes et sous-groupes de Borel, Lecture Notes in Math. 946., Berlin-Heidelberg-New York, Springer-Verlag (1982).CrossRefGoogle Scholar
[16]Spaltenstein, N., ‘Nilpotent classes and sheets of Lie algebras in bad characteristic’, Math. Z. 181 (1982), 3148.CrossRefGoogle Scholar
[17]Spaltenstein, N., ‘On unipotent and nilpotent elements of groups of type E6’, J. London Math. Soc. 27 (1983), 413420.CrossRefGoogle Scholar
[18]Spaltenstein, N., ‘Nilpotent classes in Lie algebras of type F4 over fields of characteristic 2’, J. Fac. Sci. Univ. Tokyo Sect. 1A Math. 30 (1984), 517524.Google Scholar
[19]Springer, T. A., ‘The Steinberg function of a finite Lie algebra’, Invent. Math. 58 (1980), 211216.CrossRefGoogle Scholar
[20]Springer, T. A., and Steinberg, R., ‘Conjugacy classes’, Seminar on algebraic groups and related finite groups, Borel, A. et al. (Lecture Notes in Math. 131, Berlin-Heidelberg-New York, Springer-Verlag, 1970).Google Scholar
[21]Steinberg, R., Conjugacy classes in algebraic groups (Lecture Notes in Math. 366, Berlin-Heidelberg-New York, Springer-Verlag, 1974).CrossRefGoogle Scholar
[22]Steinberg, R., Endomorphisms of linear algebraic groups (Memoirs Amer. Math. Soc. 80 (1968)).Google Scholar
[23]Stuhler, U., ‘Unipotente und nilpotente Klassen in einfachen Gruppen und Lie-Algebren vom typ G2’, Nederl. Akad. Wetensch. Proc. Ser. A 74 (1971), 365378.CrossRefGoogle Scholar
[24]Havas, G. and Nicholson, T., ‘Collection’, SYMSAC, Proceedings of the ACM symposium on symbolic and algebraic computation, (Association for Computing Machinery, New York, 1976), pp. 914.CrossRefGoogle Scholar