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On a recursive inverse eigenvalue problem. (Russian, English) Zbl 1199.15031

Zh. Vychisl. Mat. Mat. Fiz. 49, No. 5, 771-775 (2009); translation in Comput. Math., Math. Phys. 49, No. 5, 743-747 (2009).
Summary: Let \(s_1, \ldots, s_n\) be arbitrary complex scalars. It is required to construct an \(n \times n\) normal matrix \(A\) such that \(s_1\) is an eigenvalue of the leading principal submatrix \(A_i\), \(i = 1, 2, \ldots, n\). It is shown that, along with the obvious diagonal solution \(\text{diag} (s_1, \ldots, s_n)\), this problem always admits a much more interesting nondiagonal solution \(A\). As a rule, this solution is a dense matrix; with the diagonal solution, it shares the property that each submatrix \(A_i\) is itself a normal matrix, which implies interesting connections between the spectra of the neighboring submatrices \(A_i\) and \(A_{i + 1}\).

MSC:

15A18 Eigenvalues, singular values, and eigenvectors
15A29 Inverse problems in linear algebra
15B57 Hermitian, skew-Hermitian, and related matrices
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