5 papers
Gabor Frames of Totally Positive Functions: A Complete Characterization
Jaume de Dios Pont, Karlheinz Gröchenig, Lukas Liehr +2
We prove that the set of time-frequency shifts with a continuous, integrable totally positive function and lattice parameters $α…
Quantitative Constraints for Stable Sampling on the Sphere
Martin Ehler, Karlheinz Gröchenig
We derive quantitative volume constraints for sampling measures on the unit sphere that satisfy Marcinkiewicz-Zygmund inequalities of order . Using precise…
Quantitative estimates: How well does the discrete Fourier transform approximate the Fourier transform on
Martin Ehler, Karlheinz Gröchenig, Andreas Klotz
In order to compute the Fourier transform of a function on the real line numerically, one samples on a grid and then takes the discrete Fourier transform. We derive exact e…
A Characterization of Metaplectic Time-Frequency Representations
Karlheinz Gröchenig, Irina Shafkulovska
We characterize all time-frequency representations that satisfy a general covariance property: any weak*-continuous bilinear mapping that intertwines time-frequency shifts on the c…
Geodesic cycles on the Sphere: -designs and Marcinkiewicz-Zygmund Inequalities
Martin Ehler, Karlheinz Gröchenig, Clemens Karner
A geodesic cycle is a closed curve that connects finitely many points along geodesics. We study geodesic cycles on the sphere in regard to their role in equal-weight quadrature rul…