English

Algebraic values of transcendental power series with geometric coefficient moduli

Number Theory 2026-07-26 v1

Abstract

Let λ>1\lambda>1 be a real algebraic number. We construct continuum many power series f(z)=k0akzkf(z)=\sum_{k\geq0}a_kz^k of radius of convergence exactly one such that every nonzero coefficient aka_k is algebraic and has modulus λm\lambda^m for some m0m\geq0. Moreover, for every integer s0s\geq0, the derivative f(s)f^{(s)} takes algebraic values at all algebraic points of the open unit disk and is transcendental over C(z)\mathbb{C}(z). The proof combines algebraic polygonal cancellation with a sparse polynomial-block argument. This shows that a multiplicative rank-one restriction on coefficient moduli is compatible with algebraicity of the full analytic jet at every algebraic point once algebraic phases are allowed.

Keywords

Cite

@article{arxiv.2607.23851,
  title  = {Algebraic values of transcendental power series with geometric coefficient moduli},
  author = {Diego Marques},
  journal= {arXiv preprint arXiv:2607.23851},
  year   = {2026}
}