Are there any cases when the row-rank and column rank of a matrix can not be equal? Or are they equal under all circumstances?
I understand the proof that they are equal but was wondering if there are any special cases when they are not equal.
Are there any cases when the row-rank and column rank of a matrix can not be equal? Or are they equal under all circumstances?
I understand the proof that they are equal but was wondering if there are any special cases when they are not equal.
They are always equal. That's a basic theorem in Linear Algebra. You will find a proof here, for instance.
Yes, they are always equal.
Row rank is equal to the number of non-zero rows in the RREF while the column rank is equal to the number of pivot columns in the RREF.