Finite multiplicity theorems for induced representations of semisimpmle Lie groups II, -Applications to generalized Gelfand-Graev representations-
Finite multiplicity theorems for induced representations of semisimpmle Lie groups II, -Applications to generalized Gelfand-Graev representations-
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半单李群 II 的诱导表示的有限重数定理,-在广义 Gelfand-Graev 表示中的应用-
DOI:
10.1215/kjm/1250520400
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发表时间:
1988
影响因子:
--
通讯作者:
Hiroshi Yamashita
中科院分区:
文献类型:
--
作者:
Hiroshi Yamashita
This paper is the sccond part of our work o n finite multiplicity property for induced representations. We give in this article finite multiplicity theorems for generalized Gelfand-Graev representations of semisimple Lie groups, applying the results of the first part [32] (referred a s [I] later on). Let G be a connected semisimple Lie group with finite center. In [ I ] , we generalized th e result of van den Ban [1] on finiteness of multiplicities in the Plancherel formula associated to a semisimple symmetric space, developing the theory of spherical functions in a much more general setting. Furthermore, we gave there nice sufficient conditions for an induced representation of G to have finite multiplicity property. T h ese c r ite r io n s en ab le u s to understand, in a unified manner, many finite multiplicity theorems f o r induced representations, obtained in different situations ([2], [8], [26], etc.). Among others, we are interested in the following important exam p le . Let G=KA,N„, be an Iwasawa decomposition o f G . Then N n i i s a maximal unipotent subgroup of G . We showed in [I] that the induced representation Ind ,, i (e) (differentiably (=C -) o r un itarily (= V ) induced) has fin ite m ultip licity property f o r any one-dimensional representation (=character) e o f N in . (see [I, 4 .2 ]) . As wes suggested in Appendix of [I], the study of such a n induced representation is reduced, to a la r g e e x te n t , to th a t o f Inn m (e ) w ith a non-degenerate character C. T h e la tte r representation is called a Gelfand-Graev representation (=GGR fo r sh o rt) . According to Shalika [26], the GGRs have a remarkable property : the unitarily induced GGRs are of multiplicity one if G is linear and quasi-split (cf. [I, Theorem 4 .5 ]) . These GGRs have been playing an important role not only in the representation theory itself but also in the theory of automorphic fo rm s. (For the historical background of the study of GGRs, we refer to [31, 0.1].) But, in the representation theoretical p o in t o f v iew , GGRs a r e not large enough to understand all the irreducible representations through them. In other words, there exist numbers of irreducible representations of G that never "occur"