Arithmetical Applications of an Identity for the Vandermonde Determinant

Abstract

When $\{\alpha_i\}_{1 \leq i \leq m}$ is a sequence of distinct non-zero elements of an integral domain $A$ and $\gamma$ is a common multiple of the $\alpha_i$ in $A$ we obtain, by means of a simple identity for the Vandermonde determinant, a lower bound for $\sup_{1\leq i < j \leq m}\phi(\alpha_i - \alpha_j)$ in terms of $\phi(\gamma)$, where $\phi$ is a function from the nonzero elements of $A$ to ${\bf R}_{+}$ satisfying certain natural conditions. We describe several applications of this bound.