English

Estimates of Hilbert modular cusp forms of half-integral and integral weight

Number Theory 2015-10-13 v1

Abstract

Let Γ\Gamma be a cocompact, discrete, and irreducible subgroup of PSL2(R)n\mathrm{PSL}_{2}(\mathbb{R})^{n}. Let ν\nu be a unitary character of Γ\Gamma. For k1\slash2Zk\in1\slash 2\,\mathbb{Z}, let \sknu\sknu denote the complex vector space of cusp forms of weight-\tk=\k\tk=\k and nebentypus ν2k\nu^{2k} with respect to Γ\Gamma. We assume that ωX,ν\omega_{X,\nu}, the line bundle of cusp forms of weight-1\slash2~:=(1\slash2,,1\slash2)\tilde{1\slash 2}:=(1\slash 2,\ldots,1\slash2) with nebentypus ν\nu over XX exists. Let {f1,,fj\tk}\lbrace f_{1},\ldots,f_{j_{\tk}} \rbrace denote an orthonormal basis of \sknu\sknu. In this article, we show that as kk\rightarrow \infty, the sum i=1j\tkykfi(z)2\sum_{i=1}^{j_{\tk}}y^{k}|f_{i}(z)|^{2} is bounded by O(kn)O(k^{n}), where the implied constant is independent of Γ\Gamma. Furthermore, we extend these results to the case when k2Zk\in2\mathbb{Z}, and to the case when Γ\Gamma is commensurable with the Hilbert modular group ΓK:=PSL2(OK)\Gamma_{K}:=\mathrm{PSL}_{2}(O_{K}), where KK is a totally real number field of degree n2n\geq 2, and OK\mathcal{O}_{K} is the ring of integers of KK, and to the case of adelic modular forms.

Keywords

Cite

@article{arxiv.1510.02925,
  title  = {Estimates of Hilbert modular cusp forms of half-integral and integral weight},
  author = {Anilatmaja Aryasomayajula},
  journal= {arXiv preprint arXiv:1510.02925},
  year   = {2015}
}

Comments

9 pages. arXiv admin note: text overlap with arXiv:1507.00358