These are the notes of the lecture course given at LTCC in 2015. The aim of the course is to consider the following three classes of operators: Toeplitz and Hankel operators on the Hardy space on the unit circle and Toeplitz operators on the Bergman space on the unit disk. For each of these three classes of operators, we consider the following questions: boundedness and estimates or explicit ex...

The Fredholm properties of Toeplitz operators on the Bergman space A have been well-known for continuous symbols since the 1970s. We investigate the case p = 1 with continuous symbols under a mild additional condition, namely that of the logarithmic vanishing mean oscillation in the Bergman metric. Most differences are related to boundedness properties of Toeplitz operators acting on A that ari...

We discuss formal orthogonal polynomials with respect to a moment matrix that has no structure whatsoever. In the classical case the moment matrix is often a Hankel or a Toeplitz matrix. We link this to block factorization of the moment matrix and its inverse, the block Hessenberg matrix of the recurrence relation, the computation of successive Schur complements and general subspace iterative m...

We present a fast 5D (frequency and 4 spatial axes) reconstruction method that uses Multichannel Singular Spectrum Analysis / Cazdow algorithm. Rather than embedding the 4D spatial volume in a Hankel matrix, we propose to embed the data into a block Toeplitz form. Rank reduction is carried out via Lanczos bidiagonalization with fast block Toeplitz matrix-times-vector multiplications via 4D Fast...

This paper studies the normwise perturbation theory for structured least squares problems. The structures under investigation are symmetric, persymmetric, skewsymmetric, Toeplitz and Hankel. We present the condition numbers for structured least squares. AMS subject classification (2000): 15A18, 65F20, 65F25, 65F50.

The classical and intensively studied problem of solving a Toeplitz/Hankel linear system of equations is omnipresent in computations in sciences, engineering and communication. Its equivalent formulations include computing polynomial gcd and lcm, Padé approximation, and BerlekampMassey’s problem of recovering the linear recurrence coefficients. To improve the current record asymptotic bit opera...

structures on a model based on available prior informaAlgorithms are presented for least-squares approximation. Earlier work on these problems has primarily contion of Toeplitz and Hankel matrices from noise corsisted of using Singular Value Decomposition [4, 5, 81, rupted or ill-composed matrices, which may not have where only the rank information of the underlying sigcorrect structural or ran...

An infinite matrix is called irreducible if its directed graph is strongly connected. It is proved that an infinite Toeplitz matrix is irreducible if and only if almost every finite leading submatrix is irreducible. An infinite Hankel matrix may be irreducible even if all its finite leading submatrices are reducible. Irreducibility results are also obtained in the finite cases.

Applying the superfast divide-and-conquer MBA algorithm for generally singular n × n Toeplitz-like or Hankel-like integer input matrices, we perform computations in the ring of integers modulo a power of a fixed prime, especially power of 2. This is practically faster than computing modulo a random prime but requires additional care to avoid degeneration, particularly at the stages of compressi...