On representations of finite groups in the space of modular forms of half-integral weight
On representations of finite groups in the space of modular forms of half-integral weight
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半积分权模形式空间中有限群的表示
DOI:
10.3792/pjaa.70.198
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发表时间:
1994
期刊:
影响因子:
--
通讯作者:
Masaru Ueda
中科院分区:
文献类型:
--
作者:
Masaru Ueda
Introduction. Let p be a prime and k an integer. In 1940, Hecke studied a representation of SL2(Z/pZ) which is realized in the space of modular forms of level p and of weight/c and obtained beautiful results. In this paper, we study a similar representation rk+l/2 which is realized in the space of cusp forms of level 4p and of weight k + 1/2. In particular, we study in detail the subrepresentation Ps generated by Hecke common eigenforrn f of level 4p ("newform"). Then we have some completely different facts from the results in the case of integral weight. For example, ps is always irreducible, and if f is of Neben-type, whether p is "residual" or "non-residual" (cf. below (1.2)) is determined by the Atkin-Lehner involution W(p) (cf. Theorem (4.1) for the details). Finally, we remark that the class number of Q(v/p) also occurs in our results as in the classical work of Hecke (cf. Remark(4.2)). 0 Preliminaries. Throughout this paper, we keep to the notation in [4]. In particular, we use the following general notation. Let /c denote a positive integer and p an odd prime number. If z C and x C, we put zxexp(x, log(z)) with log(z) --log(lz[) +v/1 arg(z), arg(z) being determined by 7r < arg(z) _< zr. Also we put e(z) exp (2zr/I z). (a b) /,o(4) and Let gp be the complex upper half plane. For 7 c d