A square matrix is called a permutation matrix if it contain
     A square matrix is called a permutation matrix if it contains the entry 1 exactly once in each row and in each column, with all other entries being 0. All permutation matrices are invertible. Find the inverse of the permutation matrix  A = [0 0 1 0  0 0 0 1  1 0 0 0  0 1 0 0]. 
  
  Solution
The transpose of a permutation matrix is its inverse. Thus, for the given matrix its transpose it its inverse. Transpose of a matrix can be given by interchanging its rows by its columns.
 Thus A-1 = AT =
 [ 0 0 1 0
 0 0 0 1
 1 0 0 0
 0 1 0 0 ]

