Linear diophantine equations in several variables

Abstract

Let $R$ be a ring and let $(a_1,\dots ,a_n)\in R^n$ be a unimodular vector, where $n\ge 2$ and each $a_i$ is in the center of $R$. Consider the linear equation $a_1{X}_1+\cdots +a_n{X}_n=0$, with solution set $S$. Then $S=S_1+\cdots +S_n$, where each $S_i$ is naturally derived from $(a_1,\dots ,a_n)$, and we give a presentation of $S$ in terms of generators taken from the $S_i$ and appropriate relations. Moreover, under suitable assumptions, we elucidate the structure of each quotient module $S/S_i$. Furthermore, assuming that $R$ is a principal ideal domain, we provide a simple way to construct a basis of $S$ and, as an application, we determine the structure of the quotient module $S/U_i$, where each $U_i$ is a specific module containing $S_i$.