Algebraic independence of infinite series
Jaroslav Hancl, Mathias L. Laursen, Simon Kristensen
TL;DR
This work develops criteria ensuring algebraic independence for finite families of numbers given by rational-series, extending Erdős–Erdős irrationality results to the multivariate algebraic setting. By combining $p$-adic divisibility patterns with a unifying size-sequence and, in the two-series case, projective-curve genus arguments, the authors prove that the vector $(\alpha_1,\dots,\alpha_K)$ cannot satisfy any non-zero polynomial of bounded degree. The framework yields corollaries on $p$-irrationality, $p$-transcendence, and more general $\mathcal{P}$-irrationality/transcendence, and is illustrated with numerous concrete examples including sign-varying series and zeta-type sums. The results significantly broaden irrationality and independence criteria for series with rational terms, with potential applications to explicit constructions and Diophantine problems. The methods blend analytic tail estimates with algebraic-geometry tools (genus, Faltings’s theorem), providing both qualitative and quantitative criteria for independence.
Abstract
We give conditions on a finite set of series of rational numbers to ensure that they are algebraically independent. Specialising our results to polynomials of lower degree, we also obtain new results on irrationality and $mathbb{Q}$-linear independence of such series.
