arXiv subjects

Dariusz Piekarz

Publications and source records attributed to Dariusz Piekarz.

2 recordsLinked to original sources

arXiv2025

The uniqueness problem for the 3-Point Nevanlinna-Pick extremal interpolation problem in the unit Euclidean ball $\Bn{d}$

Agler and McCarthy studied the uniqueness of a 3-point interpolation problem in the bidisc. This note aims to solve an analogous problem in the unit Euclidean ball in an arbitrary dimension.

math.CV↗

arXiv2025

The von Neumann inequality for $3\times3$ matrices in the unit Euclidean ball

It is shown that the constant $c_{d,3}$ in von Neumann's inequality for d-tuples of commutative and row contractive $3\times3$ matrices, as proved by Hartz, Richter, and Shalit in [2], is independent of the size of the d-tuple. A numerical estimation of the constant is provided.

math.CV↗