In analogy with the peak points of the Shilov boundary of a uniform algebra, Arveson defined
the notion of boundary representations among the completely contractive representations of …

We give a new proof of the operator version of the Fejér-Riesz Theorem using only ideas
from elementary operator theory. As an outcome, an algorithm for computing the outer …

In this paper we find a characterization for when a multivariable trigonometric polynomial
can be written as a sum of squares. In addition, the truncated moment problem is addressed …

In order to construct two-variable polynomials with a certain zero behavior, the notion of
intersecting zeros is studied. We show that generically two-variable polynomials have a …

Mathematical engineering is concerned with the development of theoretical models, the
formulation of real-life problems using these models and the computational aspects of …

The first part is devoted to establish a useful mapping formula for functional calculus
associated with ρ-contractions. In the second part, we give a general Julia's lemma for …

Let $\mathcal {H} $ be a complex Hilbert space and let $\big\{A_ {n}\big\} _ {n\geq 1} $ be a
sequence of bounded linear operators on $\mathcal {H} $. Then a bounded operator $ B …

The purpose of this paper is to describe the Harnack parts for the operators of class Cρ (ρ>
0) on Hilbert spaces which were introduced by B. Sz.-Nagy and C. Foiaş. More precisely, we …

Model theory for hyponormal contractions Page 1 Integr. equ. oper. theory 36 (2000) 182-192
0378-620X//020182-11 $1.50+0.20/0 9 Birkl~user Verlag, Basel, 2000 l Integral Equations and …

This thesis is concerned with convex optimization problems over matrix polynomials that are
constrained to be positive semidefinite on the unit circle. Problems of this form appear in …