Show that if $\mathbf{v}_1, \ldots, \mathbf{v}_n$ span $V \neq\{\mathbf{0}\}$, then one can choose a subset $\mathbf{v}_{i_1}, \ldots, \mathbf{v}_{i_m}$ that forms a basis of $V$. Thus, $\operatorname{dim} V=m \leq n$. Under what conditions is $\operatorname{dim} V=n$ ?