Graciano Neves de Oliveira1
1Instituto Gulbenkian de Ciencia, C.C.C., Oeiras, Portugal
Tóm tắt
We shall be concerned with the following problem. Let a11, …, ann be complex numbers and λ1, …, λn nonnegative real numbers. Under what conditions does there exist an n × n complex matrix A with a11, …, ann as principal elements and λ1, …, λn as singular values? This problem has been suggested in [3] but, to our knowledge, has not yet been solved.
