On Relations of Dimensions of Automorphic Forms of $Sp(2, R)$ and Its Compact Twist $Sp(2)$ (II)
On Relations of Dimensions of Automorphic Forms of $Sp(2, R)$ and Its Compact Twist $Sp(2)$ (II)
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论$Sp(2, R)$的自守形式的维数关系及其紧扭曲$Sp(2)$ (II)
DOI:
10.2969/aspm/00710007
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发表时间:
1985
期刊:
影响因子:
--
通讯作者:
T. Ibukiyama
中科院分区:
文献类型:
--
作者:
K. Hashimoto;T. Ibukiyama
In this paper, we show some good global dimensional relations between automorphic forms of Sp(2, R) (matrix size four) and its compact twist Sp(2). One of the authors has already shown such relations when the p-adic completions (for a fixed prime p) of the discrete subgroups in question are maximal compact (See [24]). In this paper, we treat discrete subgroups whose p-adic completions are minimal parahoric. Our aim is a generalization of Eichler-Jacquet-Langlands correspondence between SLz and SU(2) to the symplectic case of higher degree. Such correspondence should be proved by comparison of the traces of all the Hecke operators. Our results mean that there exist relations of traces at least for T(I) for some explicitly defined discrete subgroups of Sp(2, R) and Sp(2) (§ 2 Main Theorem I). Besides, they give meaningful examples for Langlands philosophy on stable conjugacy classes (§ 2 Main Theorem II). Roughly speaking, such comparison is divided into character relations at infinite places (which are more or less known) and arithmetics at finite places. Our point is to execute the comparison of the arithmetical part explicitly. It seems that our Theorems are the first global results on such relations except for GLn (cf. also [24]). In Section 1, after a brief introduction, we give a precise formulation on our problems between Sp(n, R) and Sp(n) for general n, e.g. on how to choose discrete subgroups explicitly. For automorphic forms with respect to these explicitly chosen discrete subgroups, we propose there two conjectures (which were first given in [21], [23]): coincidence of dimensions and existence of an isomorphism between new forms as Hecke algebra modules. For n= 1, these are nothing but the theorems by Eichler [10], [11], and the above conjectures are a natural generalization of his results. Langlands [34] has given a quite general philosophy on correspondence of automorphic forms of any reductive algebraic groups, but we understand that his philosophy does not give very detailed formulation at present for such typical and explicit cases as