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$p$-adic Properties for Taylor Coefficients of Half-integral Weight Modular Forms on $\Gamma_1(4)$

Number Theory 2022-09-07 v2

Abstract

For a prime p3p\equiv 3 (mod 4)(\text{mod }4) and m2m\ge 2, Romik raised a question about whether the Taylor coefficients around 1\sqrt{-1} of the classical Jacobi theta function θ3\theta_3 eventually vanish modulo pmp^m. This question can be extended to a class of modular forms of half-integral weight on Γ1(4)\Gamma_1(4) and CM points; in this paper, we prove an affirmative answer to it for primes p5p\ge5. Our result is also a generalization of the results of Larson and Smith for modular forms of integral weight on SL2(Z)\mathrm{SL}_2(\mathbb{Z}).

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Cite

@article{arxiv.2109.08778,
  title  = {$p$-adic Properties for Taylor Coefficients of Half-integral Weight Modular Forms on $\Gamma_1(4)$},
  author = {Jigu Kim and Yoonjin Lee},
  journal= {arXiv preprint arXiv:2109.08778},
  year   = {2022}
}

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17 pages