An intrinsic analysis of unitarizable highest weight modules
An intrinsic analysis of unitarizable highest weight modules
复制标题
可统一化最高权重模块的内在分析
DOI:
10.1007/bf01444551
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发表时间:
1990
影响因子:
1.4
通讯作者:
A. Joseph
中科院分区:
文献类型:
--
作者:
T. Enright;A. Joseph
1.1. Let g be a complex simple Lie algebra. In this article we are concerned with unitarizable highest weight modules for a real form go of~. These modules were classified in I-EHW] and [Ja]. In both of these classifications the arguments relied on the Howe theory of dual pairs for the classical cases SU (p, q), Mp (2n, P,.) and SO*(2n) or the corresponding results of Kashiwara and Vergne I-KV] for SU (p, q) and Mp (2n, R). For the remaining classical cases as well as all the exceptional cases the arguments included a variety of very detailed case by case calculations of reducibility and f-structure.1.2. In [P](see also [EHW, 3.6 and 3.9]) a careful manipulation of Casimir elements gives a set of norm inequalities, which we call the Parthasarathy inequalities, and shows that unitarity is equivalent to the validity of this set of norm inequalities for the f-highest weights in the module. Both [EHW] and [Ja] use this analysis of unitarity by~-structure for some case by case considerations of the last point of unitarity. Here we analyze the~-structure of highest weight modules in the general setting to give necessary conditions for unitarity. We then use the same inequalities to prove the unitarity of the last reduction point as well as the modules in what is called the Wallach set i-W1, W2]. Finally we complete the proof of unitarity by using Jakobsen's trick of tensoring the module at the last reduction point with the modules in the WaUach set. In the present work we believe the analysis to be quite novel, rather elementary and essentially case by case free. In particular our arguments do not appeal to