摘要
Let J. be an n × n Jacobi matrix and Al λ1 ,..',λ2n distinct real numbers. The following problem is well known. Under what condition does there exist a 2n × 2n Jacobi matrix J. such that J,. has eigenvalues λ1, ..λ2n A. and its leading n × n principal submatrix is exactly Jn In this paper a condition for the solubility of the problem is given. The dependence of J2n on the given data is shown to be continuous.
