O. Christensen

activity

19952021

most citedOperator representations of frames: boundedness, duality, and stability

37 citations · 118 across the 21 of their papers we have counts for

collaborators

30 papers

math.FA2021

A survey on frame representations via dynamical sampling

Ole Christensen, Marzieh Hasannasab

Dynamical sampling deals with representations of a frame ${f_{k}}_{k = 1}^{\infty}$ as an orbit ${T^{n} φ}_{n = 0}^{\infty}$ of a linear and possibly bounded operator $T$ acting on the…

math.FA2021

Approximately dual pairs of wavelet frames

Ana Benavente, Ole Christensen, Marzieh Hasannasab +3

This paper deals with structural issues concerning wavelet frames and their dual frames. It is known that there exist wavelet frames $\{a^{j/2}ψ( a^j\cdot -kb)\}_{j,k\in \mathbb Z}…

math.FA2021

Completion versus removal of redundancy by perturbation

Ole Christensen, Marzieh Hasannasab

A sequence ${g_{k}}_{k = 1}^{\infty}$ in a Hilbert space $H$ has the expansion property if each $f \in span {g_{k}}_{k = 1}^{\infty}$ has a representation $f= \sum_{k…

math.FA2021

On approximate operator representations of sequences in Banach spaces

Ole Christensen, Marzieh Hasannasab, Gabriele Steidl

Generalizing results by Halperin et al., Grivaux recently showed that any linearly independent sequence ${f_{k}}_{k = 1}^{\infty}$ in a separable Banach space $X$ can be represented as…

math.FA2019

Approximate frame representations via iterated operator systems

Ole Christensen, Marzieh Hasannasab

It is known that it is a very restrictive condition for a frame ${f_{k}}_{k = 1}^{\infty}$ to have a representation ${T^{n} φ}_{n = 0}^{\infty}$ as the orbit of a bounded operator $T$ und…

math.FA2018

Frame Properties of Operator Orbits

Ole Christensen, Marzieh Hasannasab, Friedrich Philipp

We consider sequences in a Hilbert space $H$ of the form $(T^{n} f_{0})_{n \in I},$ with a linear operator $T$ , the index set being either $I = N$ or $I = Z$ , a…