R. B. Alexeev

collaborators

3 papers

math.FA2001

Badly approximable matrix functions and canonical factorizations

R. B. Alexeev, V. V. Peller

We continue studying the problem of analytic approximation of matrix functions. We introduce the notion of a partial canonical factorization of a badly approximable matrix function…

math.FA2001

Unitary interpolants and factorization indices of matrix functions

R. B. Alexeev, V. V. Peller

For an $n \times n$ bounded matrix function $Φ$ we study unitary interpolants $U$ , i.e., unitary-valued functions $U$ such that $U^(j) = Φ^(j)$ , $j < 0$ . We are looking for unita…

math.FA2001

Invariance properties of thematic factorizations of matrix functions

R. B. Alexeev, V. V. Peller

We study the problem of invariance of indices of thematic factorizations. Such factorizations were introduced in [PY1] for studying superoptimal approximation by bounded analytic m…