The Perturbation of Elements of Nonnegative Definite Matrices and Positive Definite Completion
Hu Yang · Advances in Mathematics · 2006
This paper studies the range of its elements permitted to ensure nonnegative definite matrices keep nonnegative. Compared with the positive definite completions problem of partial hermitian matrices by C. R. Johnson, we find our result is simpler than C. R. Johnson's in the matter of studying the range of elements of completely known positive definite matrices. Moreover, we give another formula of positive definite completion problem different from C. R. Johnson's, and some properties of all these positive definite completion matrices.