Matrix theory on skew field is one of the basic direction in non-exchange
algebra research.And the rank of matrix on skew field is an important digital
feature of matrix. The inequality (equality)of rank of matrix is one of
the important issues newly discussed in the matrix theory. For the proof of
matrix-rank inequality(equality),the paper firstly makes use of some matrices
to construct block matrix ,then proves the inequality(equality)of rank of matrix
by doing generalized elementary transformation to the block matrix above
,therefore some well-known inequalities can be proved by this method.