# Math Help - question involving matrix row column rank proof

1. ## question involving matrix row column rank proof

Let A be an $m \times n$ matrix. If $k \leq m$ and $l \leq n$ , then a $k \times l$ matrix $B$ is said
to be a submatrix of $A$, if $B$can be obtained from $A$ by deleting some set of $m-k$rows and $n-l$columns of $A$.
if we define the determinantal rank of $A$ to be the largest $k$for which $A$ has a $k \times k$
submatrix with non-zero determinant. Show that this is equal to the usual row or
column rank of $A$.