The goal of this paper is to obtain lower bounds on the height of an algebraic number in a relative setting, extending previous work of Amoroso and Masser. Specifically, in our first theorem we obtain an effective bound for the height of an algebraic number $\alpha$ when the base field $\mathbb{ K}$ is a number field and $\mathbb{ K}(\alpha)/\mathbb{ K}$ is Galois. Our second result establishes an explicit height bound for any non-zero element $\alpha$ which is not a root of unity in a Galois extension $\mathbb{ F}/\mathbb{ K}$, depending on the degree of $\mathbb{ K}/\mathbb{ Q}$ and the number of conjugates of $\alpha$ which are multiplicatively independent over $\mathbb{ K}$. As a consequence, we obtain a height bound for such $\alpha$ that is independent of the multiplicative independence condition.
Categories: math.NT