The preserver problems of positive semidefinite matrix
Ren Fang-guo · Basic Sciences Journal of Textile Universities · 2011
By using the classical conditions of equivalence of semidefinite Hermite block matrix sufficiently,the problem of maintaining semidefiniteness with two by two block matrix are mainly discussed.Firstly,if A∈Mn is a positive semidefinite Hermite block matrix,the resulting matrix that is taken trace,determinant,spectrum norm,rank and numerical radius for every block matrix respectively is still positive semidefinite.Secondly,if A∈Mn is a block matrix,the norm and numerical radius of A are not exceeded that of .