8 citations · 36 across the 32 of their papers we have counts for
13 papers · 1 filter
A note on the invertibility of the Gabor frame operator on certain modulation spaces
Dae Gwan Lee, Friedrich Philipp, Felix Voigtlaender
We consider Gabor frames generated by a general lattice and a window function that belongs to one of the following spaces: the Sobolev space , the weighted…
Time-Frequency Shift Invariance of Gabor Spaces with an -Generator
Andrei Caragea, Dae Gwan Lee, Friedrich Philipp +1
We consider Gabor Riesz sequences generated by a lattice and a window function which is well localized in both time and frequency. W…
A quantitative subspace Balian-Low theorem
Andrei Caragea, Dae Gwan Lee, Friedrich Philipp +1
Let be the subspace spanned by a Gabor Riesz sequence with and a lattice of rational density.…
Finite Rank Perturbations of Linear Relations and Matrix Pencils
Leslie Leben, Francisco Martínez-Pería, Friedrich Philipp +2
We elaborate on the deviation of the Jordan structures of two linear relations that are finite-dimensional perturbations of each other. We compare their number of Jordan chains of…
Frame Properties of Operator Orbits
Ole Christensen, Marzieh Hasannasab, Friedrich Philipp
We consider sequences in a Hilbert space of the form with a linear operator , the index set being either or , a…
A Balian-Low Theorem for Subspaces
A. Caragea, D. Lee, G. E. Pfander +1
We extend the Balian-Low theorem to Gabor subspaces of by involving the concept of additional time-frequency shift invariance. We prove that if a Gabor system on a…
Dynamical Sampling on Finite Index Sets
C. Cabrelli, U. Molter, V. Paternostro +1
We consider bounded operators acting iteratively on a finite set of vectors in a Hilbert space and address the problem of providing necessary an…
Bessel orbits of normal operators
Friedrich Philipp
Given a bounded normal operator in a Hilbert space and a fixed vector , we elaborate on the problem of finding necessary and sufficient conditions under which $(A^kx)_{k\in\…
The effect of perturbations of linear operators on their polar decomposition
Richard Duong, Friedrich Philipp
The effect of matrix perturbations on the polar decomposition has been studied by several authors and various results are known. However, for operators between infinite-dimensional…
The Effect of Perturbations of Operator-Valued Frame Sequences and Fusion Frames on Their Duals
Gitta Kutyniok, Victoria Paternostro, Friedrich Philipp
Fusion frames, and, more generally, operator-valued frame sequences are generalizations of classical frames, which are today a standard notion when redundant, yet stable sequences…
Measures of scalability
Xuemei Chen, Gitta Kutyniok, Kasso A. Okoudjou +2
Scalable frames are frames with the property that the frame vectors can be rescaled resulting in tight frames. However, if a frame is not scalable, one has to aim for an approximat…
Phase Retrieval from 4N-4 Measurements
Friedrich Philipp
We prove by means of elementary methods that phase retrieval of complex polynomials p of degree less than N is possible with 4N-4 phaseless Fourier measurements of p and p'. In add…
The numerical range of non-negative operators in Krein spaces
Friedrich Philipp, Carsten Trunk
We define and characterize the Krein space numerical range and the Krein space co-numerical range of a non-negative operator in a Krein space. It is show…