Normal matrix 正规矩阵
(重定向自Normal transformation)
In mathematics, a complex square matrix A is normal if
where A is the conjugate transpose of A. That is, a matrix is normal if it commutes with its conjugate transpose.
A real square matrix A satisfies A = A, and is therefore normal if AA = AA.
Normality is a convenient test for diagonalizability: a matrix is normal if and only if it is unitarily similar to a diagonal matrix, and therefore any matrix A satisfying the equation AA = AA is diagonalizable.