The normalizer of a set of matrices contained in a Lie algebra of matrices is the Lie algebra of matrices for all When  is a Lie algebra, is an ideal in

A list of vectors defining a basis for the normalizer of is returned.

For the first calling sequence the normalizer of is calculated in the Lie algebra of all matrices, where is the row dimension of the matrices in

The command MatrixNormalizer is part of the DifferentialGeometry:-LieAlgebras package.  It can be used in the form MatrixNormalizer(...) only after executing the commands with(DifferentialGeometry) and with(LieAlgebras), but can always be used by executing DifferentialGeometry:-LieAlgebras:-MatrixNormalizer(...).