Unramified Whittaker functions for GL(3,R)
Unramified Whittaker functions for GL(3,R)
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DOI:
10.1007/bf02788764
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发表时间:
1995-01-01
影响因子:
1
通讯作者:
Huntley, J
中科院分区:
文献类型:
--
作者:
Bump, D;Huntley, J
In this paper, we will present a portion of the theory of GL (3,~) Whittaker functions which is obtainable using elementary methods of the theory of complex variables. We will study the asymptotic expansions at infinity for spherical Whittaker functions on GL (3, R). These Whittaker functions are solutions to an overdetermined system of partial differential equations in two variables, having six solutions, which is a rank two analog of the confluent hypergeometric equation. We will obtain asymptotic expansions for all six solutions, allowing us to characterize the one particular solution which occurs in the Fourier expansions of automorphic forms by a condition of moderate growth at infinity.(Results of this type may also be found in Wallach [11] and Shalika [7].) We also compute the higher order terms in the asymptotic expansions, which may have applications to automorphic forms. Asymptotic expansions of Whittaker functions on an arbitrary reductive Lie group have been considered by Wallach [11] using methods of representation theory. Wallach's results, which overlap with ours, are definitive. However, we are able to obtain extremely precise information, which is new, by restricting to the particular example of GL (3, R). We will discuss the relationship between our work and Wallach's in Section 2.We find that (in the region under consideration) the first order asymptotics of the Whittaker functions are independent of the indexing character of the universal enveloping algebra. However, the higher order asymptotics depend upon the indexing character. In view of the methods of Huntley [4], it seems likely that this dependence of the higher order asymptotics will have implications for automorphic forms.