The Dynkin diagram $R$-group
HTML articles powered by AMS MathViewer
- by Dana Pascovici
- Represent. Theory 5 (2001), 1-16
- DOI: https://doi.org/10.1090/S1088-4165-01-00104-2
- Published electronically: January 18, 2001
- PDF | Request permission
Abstract:
We define an abelian group from the Dynkin diagram of a split real linear Lie group with abelian Cartan subgroups, $G$, and show that the $R_{\delta , 0}$-groups defined by Knapp and Stein are subgroups of it. The proof relies on Vogan’s approach to the $R$-groups. The $R$-group of a Dynkin diagram is easily computed just by looking at the diagram, and so it gives, for instance, quick proofs of the fact that the principal series with zero infinitesimal character of the split groups $E_6$, $E_8$, $G_2$ or $F_4$ are irreducible. The Dynkin diagram subgroup also implicitly describes a small Levi subgroup, which we hope might play a role in computing regular functions on principal nilpotent orbits. We present in the end a conjecture and some evidence in this direction.References
- A. W. Knapp and E. M. Stein, Irreducibility theorems for the principal series, Conference on Harmonic Analysis (Univ. Maryland, College Park, Md., 1971), Lecture Notes in Math., Vol. 266, Springer, Berlin, 1972, pp. 197–214. MR 0422512, DOI 10.1007/BFb0059645
- A. W. Knapp and Gregg Zuckerman, Classification of irreducible tempered representations of semi-simple Lie groups, Proc. Nat. Acad. Sci. U.S.A. 73 (1976), no. 7, 2178–2180. MR 460545, DOI 10.1073/pnas.73.7.2178
- G. Lusztig and N. Spaltenstein, Induced unipotent classes, J. London Math. Soc. (2) 19 (1979), no. 1, 41–52. MR 527733, DOI 10.1112/jlms/s2-19.1.41 p D. Pascovici, Regular functions on Principal Nilpotent Orbits and $R$-groups, Ph.D. Disertation, Cambridge, MIT, 2000.
- Ichirô Satake, On representations and compactifications of symmetric Riemannian spaces, Ann. of Math. (2) 71 (1960), 77–110. MR 118775, DOI 10.2307/1969880
- Wilfried Schmid, On the characters of the discrete series. The Hermitian symmetric case, Invent. Math. 30 (1975), no. 1, 47–144. MR 396854, DOI 10.1007/BF01389847
- Jir\B{o} Sekiguchi, Remarks on real nilpotent orbits of a symmetric pair, J. Math. Soc. Japan 39 (1987), no. 1, 127–138. MR 867991, DOI 10.2969/jmsj/03910127
- David A. Vogan Jr., Representations of real reductive Lie groups, Progress in Mathematics, vol. 15, Birkhäuser, Boston, Mass., 1981. MR 632407
- David A. Vogan Jr., The algebraic structure of the representation of semisimple Lie groups. I, Ann. of Math. (2) 109 (1979), no. 1, 1–60. MR 519352, DOI 10.2307/1971266
Bibliographic Information
- Dana Pascovici
- Affiliation: Department of Mathematics, Purdue University, MATH 602, West Lafayette, Indiana 47906
- Email: pascovic@math.purdue.edu
- Received by editor(s): May 31, 2000
- Received by editor(s) in revised form: October 10, 2000
- Published electronically: January 18, 2001
- © Copyright 2001 American Mathematical Society
- Journal: Represent. Theory 5 (2001), 1-16
- MSC (2000): Primary 22E46; Secondary 22E45
- DOI: https://doi.org/10.1090/S1088-4165-01-00104-2
- MathSciNet review: 1826426