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Shimura lifting on weak Maass forms

Youngju Choie, Subong Lim (2016)

Acta Arithmetica

There is a Shimura lifting which sends cusp forms of a half-integral weight to holomorphic modular forms of an even integral weight. Niwa and Cipra studied this lifting using the theta series attached to an indefinite quadratic form; later, Borcherds and Bruinier extended this lifting to weakly holomorphic modular forms and harmonic weak Maass forms of weight 1/2, respectively. We apply Niwa's theta kernel to weak Maass forms by using a regularized integral. We show that the lifted function satisfies...

Shimura varieties with Γ 1 ( p ) -level via Hecke algebra isomorphisms: the Drinfeld case

Thomas J. Haines, Michael Rapoport (2012)

Annales scientifiques de l'École Normale Supérieure

We study the local factor at  p of the semi-simple zeta function of a Shimura variety of Drinfeld type for a level structure given at  p by the pro-unipotent radical of an Iwahori subgroup. Our method is an adaptation to this case of the Langlands-Kottwitz counting method. We explicitly determine the corresponding test functions in suitable Hecke algebras, and show their centrality by determining their images under the Hecke algebra isomorphisms of Goldstein, Morris, and Roche.

Shintani and Shimura lifts of cusp forms on certain arithmetic groups and their applications

SoYoung Choi, Chang Heon Kim (2017)

Open Mathematics

For an odd and squarefree level N, Kohnen proved that there is a canonically defined subspace [...] S κ + 1 2 n e w ( N ) ⊂ S κ + 1 2 ( N ) , and S κ + 1 2 n e w ( N ) and S 2 k n e w ( N ) S κ + 1 2 n e w ( N ) S κ + 1 2 ( N ) , and S κ + 1 2 n e w ( N ) and S 2 k n e w ( N ) are isomorphic as modules over the Hecke algebra. Later he gave a formula for the product [...] a g ( m ) a g ( n ) ¯ a g ( m ) a g ( n ) ¯ of two arbitrary Fourier coefficients of a Hecke eigenform g of halfintegral weight and of level 4N in terms of certain cycle integrals of the corresponding form f of integral weight. To this...

Sign changes of certain arithmetical function at prime powers

Rishabh Agnihotri, Kalyan Chakraborty (2021)

Czechoslovak Mathematical Journal

We examine an arithmetical function defined by recursion relations on the sequence { f ( p k ) } k and obtain sufficient condition(s) for the sequence to change sign infinitely often. As an application we give criteria for infinitely many sign changes of Chebyshev polynomials and that of sequence formed by the Fourier coefficients of a cusp form.

Simple zeros of degree 2 L -functions

Andrew R. Booker (2016)

Journal of the European Mathematical Society

We prove that the complete L -functions of classical holomorphic newforms have infinitely many simple zeros.

Slopes of modular forms and congruences

Douglas L. Ulmer (1996)

Annales de l'institut Fourier

Our aim in this paper is to prove congruences between on the one hand certain eigenforms of level p N and weight greater than 2 and on the other hand twists of eigenforms of level p N and weight 2. One knows a priori that such congruences exist; the novelty here is that we determine the character of the form of weight 2 and the twist in terms of the slope of the higher weight form, i.e., in terms of the valuation of its eigenvalue for U p . Curiously, we also find a relation between the leading terms of...

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