The cofactor matrix of a given matrix is said to be the adjoint of that matrix. Any matrix that can be written as (A) also has an adjoint, which is written as adj (A). Also, if you multiply the matrix by its inverse, you will get A-1, which is the identity matrix. You could even say that an identity matrix is a unit matrix where both the matrix A and its inverse are (n x m) square matrices with ones on one diagonal and zeros everywhere else.