We give a simple proof of a recent result of Gollin and Jo\'o: if a possibly infinite system of homogeneous linear equations $A\vec{x} = \vec{0}$, where $A = (a_{i, j})$ is an $I \times J$ matrix, has only the trivial solution, then there exists an injection $\phi: J \to I$, such that $a_{\phi(j), j} \neq 0$ for all $j \in J$.
翻译:我们简单地证明Gollin和Jo\'o最近的结果:如果一个可能无限的单一线性方程式系统 $A\vec{x}=\vec{0}$, 其中$A=(a ⁇ i,j})$是美元=(a ⁇ i,j}) 美元为美元=乘J$矩阵,只有微不足道的解决方案,那么就有一个注射$:J\phi:J\to I$,例如$ ⁇ phi(j),j}\neq 0$,所有$j $。