In mathematics the determinant is an operator which has certain useful identities.
Contents
Identities
For square matrices A and B of equal size,
If A is a triangular matrix, i.e. ai,j = 0 whenever i > j or, alternatively, whenever i < j, then its determinant equals the product of the diagonal entries:
Schur complement
The following identity holds for a Schur complement of a square matrix:
The Schur complement arises as the result of performing a block Gaussian elimination by multiplying the matrix M from the right with the "block lower triangular" matrix
Here Ip denotes a p×p identity matrix. After multiplication with the matrix L the Schur complement appears in the upper p×p block. The product matrix is
That is, we have shown that