The FEniCS Project set out in 2003 with an idea to automate the solution of mathematical
models based on differential equations. Initially, the FEniCS Project consisted of two …

Currently there is a growing interest in semiseparable matrices and generalized
semiseparable matrices. To gain an appreciation of the historical evolution of this concept …

Our interest in structured matrices was inspired by the outstanding mathematician Professor
Israel Gohberg, our older friend, colleague and teacher. His ideas, projects and our joint …

We study a class of block structured matrices R={Rij} i, j= 1N with a property that the solution
of the corresponding system Rx= y of linear algebraic equations may be performed for O (N) …

In this paper the definition of semiseparable matrices is investigated. Properties of the
frequently used definition and the corresponding representation by generators are deduced …

Univariate polynomial root-finding is the oldest classical problem of mathematics and
computational mathematics, and is still an important research topic, due to its impact on …

The QR-algorithm is a renowned method for computing all eigenvalues of an arbitrary
matrix. A preliminary unitary similarity transformation to Hessenberg form is indispensable …

We prove that the unitary factor appearing in the QR factorization of a suitably defined
rational Krylov matrix transforms a Hermitian matrix having pairwise distinct eigenvalues into …

We provide a new representation for the inverse of block tridiagonal and banded matrices.
The new representation is shown to be numerically stable over a variety of block tridiagonal …

In this paper we discuss the structure of the factors of a QR-and a URV-factorization of a
diagonal-plus-semiseparable matrix. The Q-factor of a QR-factorization has the diagonal …