Integer Coefficient Power Series with Prescribed Zero Sets

Abstract

We prove that a discrete effective divisor on the open unit disk $\mathbb{D}$ is the zero divisor of a holomorphic function on $\mathbb{D}$ with integer Taylor coefficients if and only if it is invariant under complex conjugation. The construction uses a one-parameter deformation of the Weierstrass elementary factors in which each modified factor of order $n$ leaves all Taylor coefficients of degree $\leq n$ unchanged while shifting the coefficient of degree $n+1$ by a controlled affine amount. These modified factors act as elementary jet-correction operators: the triangular structure of the coefficient map permits an inductive rounding scheme compatible with canonical-product convergence. As a consequence, every holomorphic function on $\mathbb{D}$ differs from one with Gaussian-integer Taylor coefficients by multiplication by a nowhere-vanishing holomorphic factor.