1 citations · 1 across the 2 of their papers we have counts for
3 papers
math.GN2023★ 1 cited
Extensive approach to absolute homogeneity
Piotr Niemiec
The main aim of the paper is to study in greater detail absolutely homogeneous structures (that is, objects with the property that each partial isomorphism extends to a global auto…
math.FA2020
Positive Hankel operators, positive definite kernels and related topics
Piotr Niemiec
It is shown that a positive (bounded linear) operator on a Hilbert space with trivial kernel is unitarily equivalent to a Hankel operator that satisfies double positivity condition…
math.FA2020
A note on functions preserving positive definiteness
Piotr Niemiec
The aim of the paper is to give a full characterization of functions f from I into the real line R (where I is an interval in R that satisfies certain natural conditions) such that…