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Casimir Operators and Nilpotent Radicals

Published online by Cambridge University Press:  20 November 2018

J. C. Ndogmo*
Affiliation:
School of Mathematics, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africae-mail: jean-claude.ndogmo@wits.ac.za
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Abstract

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It is shown that a Lie algebra having a nilpotent radical has a fundamental set of invariants consisting of Casimir operators. A different proof is given in the well known special case of an abelian radical. A result relating the number of invariants to the dimension of the Cartan subalgebra is also established.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2012

References

[1] Abellanas, L. and Alonso, L. Martinez, A general setting for Casimir invariants. J. Mathematical Phys. 16(1975), 15801584. http://dx.doi.org/10.1063/1.522727 Google Scholar
[2] Bernat, P., Sur le corps des quotients de l’algèbre enveloppante d’une algèbre de Lie. C. R. Acad. Sci. Paris. 254(1962), 17121714.Google Scholar
[3] Boyko, V., Patera, J., and Popovych, R., Invariants of triangular Lie algebras. J. Phys. A 40(2007), no. 27 75577572. http://dx.doi.org/10.1088/1751-8113/40/27/009 Google Scholar
[4] Boyko, V., Patera, J., and Popovych, R., Invariants of triangular Lie algebras with one nil-independent diagonal element. J. Phys. A 40(2007), no. 32, 97839792. http://dx.doi.org/10.1088/1751-8113/40/32/005 Google Scholar
[5] Campoamor-Stursberg, R., Some remarks concerning the invariants of rank one solvable real Lie algebras. Algebra Colloq. 12(2005), no. 3, 497518.Google Scholar
[6] Chevalley, C., Théorie des groupes de Lie. III. Hermann, Paris, 1955.Google Scholar
[7] Dixmier, J., Sur l’algébre enveloppante d’une algébre de Lie nilpotente. Arch. Math. 10(1959), 321326. http://dx.doi.org/10.1007/BF01240805 Google Scholar
[8] Dixmier, J., Sur les représentations unitaires des groupes de Lie nilpotents II, Bull. Soc. Math. France 85 (1957), 325388.Google Scholar
[9] Dixmier, J., Algèbres enveloppantes. Gauthier-Villars, Paris, 1974.Google Scholar
[10] Humphreys, J. E., Introduction to Lie algebras and Representation Theory. Graduate Texts in Mathematics 9. Springer-Verlag, New York 1972.Google Scholar
[11] Jacobson, N., Lie Algebras. Interscience Tracts in Pure and Applied Mathematics 10. John Wiley & Sons, New York, 1962.Google Scholar
[12] Letellier, E. D., Deligne-Lusztig induction for invariant functions on finite Lie algebras of Chevalley's type. Tokyo J. Math. 28(2005), no. 1, 265282. http://dx.doi.org/10.3836/tjm/1244208292 Google Scholar
[13] Ndogmo, J. C., Invariants of a semi-direct sum of Lie algebras. J. Phys. A 37(2004), no. 21, 56355647. http://dx.doi.org/10.1088/0305-4470/37/21/009 Google Scholar
[14] Ndogmo, J. C., Properties of the invariants of solvable Lie algebras. Canad. Math. Bull. 43(2000), no. 4, 459471. http://dx.doi.org/10.4153/CMB-2000-054-0 Google Scholar
[15] Olver, P. J., Applications of Lie Groups to Differential Equations. Second edition. Graduate Texts in Mathematics 107. Springer-Verlag, New York, 1993.Google Scholar
[16] Pecina-Cruz, J. N., An algorithm to calculate the invariants of any Lie algebra. J. Math. Phys. 35(1994), no. 6, 31463162. http://dx.doi.org/10.1063/1.530458 Google Scholar
[17] Perroud, M., The fundamental invariants of inhomogeneous classical groups. J. Math. Phys 24(1983), no. 6, 13811391. http://dx.doi.org/10.1063/1.525870 Google Scholar
[18] Racah, G., Sulla caratterizzazione delle rappresentazioni irriducibli dei gruppi semisemplici di Lie. Atti Accad. Naz. Lincei. Rend. Cl. Sci. Fis. Mat. Nat. 8(1950), 108112.Google Scholar
[19] Rentschler, R., Sur le centre du corps enveloppant d’une algèbre de Lie résoluble. C. R. Acad. Sci. Paris Sér. A-B 276(1973), A21A24.Google Scholar
[20] Snobl, L. and Winternitz, P., A class of solvable Lie algebras and their Casimir invariants. J. Phys. A 38(2005), no. 12, 26872700. http://dx.doi.org/10.1088/0305-4470/38/12/011 Google Scholar
[21] Snobl, L. and Winternitz, P., All solvable extensions of a class of nilpotent Lie algebras of dimension n and degree of nilpotency n – 1. J. Phys. A 42(2009), no. 10, 105201. http://dx.doi.org/10.1088/17518113/42/10/105201 Google Scholar