The Maaß space and Hecke operators
The Maaß space and Hecke operators
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Maaß 空间和 Hecke 算子
DOI:
10.1007/bf02570891
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发表时间:
1990
影响因子:
0.8
通讯作者:
A. Krieg
中科院分区:
文献类型:
--
作者:
A. Krieg
H. Maag [20] introduced the so-called Spezialschar in 1979. Later on [21] he investigated the analogue of the Spezialschar for Siegel modular forms of degree 2 with respect to the non-trivial multiplier system. For Hermitian modular forms associated with the Gaussian number field the corresponding MaaB space was described by Kojima [11]. The invariance of these MaaB spaces under Hecke operators was demonstrated by Andrianov [1], MaaB [21], resp. Gritsenko [7].The analogue of the Spezialschar on the half-space of quaternions of degree two was introduced in [-13]. In this paper we show that the MaaB space is invariant under all Hecke operators. As a consequence we can conclude that the Siegel-Eisenstein-series always belongs to the MaaB space, as it was already announced in [-13]. We can compute the image of the Siegel-Eisenstein-series under the isomorphism between the Maal3 space and a certain subspace of the space of elliptic modular forms in El3]. As a consequence we can calculate the Fourier coefficients of the Siegel-Eisenstein-series explicitly. Surprisingly the structure of these Fourier coefficients is much simpler than the structure of the Fourier coefficients of the Siegel-Eisenstein-series in the Spezialschar (cf.[19]) resp. of the Siegel-Eisenstein-series on the Hermitian half-space (cf.[22]). The explicit description of the Fourier coefficients allows us to verify a particular case of a conjecture of Resnikoff-Saldafia [26] on the growth of the Fourier coefficients of the Siegel-Eisenstein-series E~. The knowledge of the Fourier expansion also enables us to have a closer look at the restriction map from the half-space of quaternions to the Siegel half-space of degree 2. We already know that this restriction maps theta series onto theta series (cf.[12], IV, w 1). But the restriction does not map the Siegel-Eisenstein-series on H (2; IH) onto the Siegel-Eisenstein-series on H (2; ll) in general. Here an additional cusp form appears. Moreover we introduce two types of Dirichlet series associated with modular forms in the Maag space. The first one arises from the first Jacobi form in the Fourier-Jacobi-expansion. The second one is the Andrianov zeta function.