Mahler Method and Vanishing Theorem

Abstract

This paper is motivated by the recent work of Adamczewski and Faverjon [5], who established the algebraic independence of values of Mahler functions satisfying linear functional equations. While their work is a landmark result, some proofs are long and complex. The primary aim of this paper is to simplify those proofs and provide new applications. In their proofs, a vanishing theorem for polynomials, rather than power series, is sufficient. We give a proof of the vanishing theorem without using Szemer\'edi's theorem or Corvaja-Zannier's theorem. In the case of a single transformation, we present a refined vanishing theorem, which allows us to simplify the proof of algebraic independence. We also provide an elementary proof of a vanishing theorem for $q_i$-Mahler functions with various $q_i$. As an application, we prove the algebraic independence of certain continued fractions, extending previous results by Han\v{c}l, Adamczewski, and Bundschuh and V\"a\"an\"anen in which only linear independence and transcendence had been established.