Gelfond-Schneider Theorem/Lemma 4

Lemma
Let:
 * $\Delta = \det \sqbrk {\alpha_{i, j} }_{L \times L}$

where the $\alpha_{i, j}$ are algebraic numbers.

Suppose that $T$ is a positive (rational) integer for which $T \alpha_{i, j}$ is an algebraic integer for every $i, j \in \set {1, 2, \ldots, L}$.

Also, suppose that $\Delta \ne 0$.

Then there is a conjugate of $\Delta$ with absolute value $\ge T^{−L}$.

Proof
Observe that $T^L \Delta$ is an algebraic integer so that one of its conjugates has absolute value $\ge 1$.

The result follows.