3,174 reputation
1348
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years, 2 months
seen 18 mins ago

Professor at TU Braunschweig.

Area: Inverse problems, regularization theory, applied functional analysis, mathematical image processing.


Nov
14
reviewed Approve Graph automorphism that swaps two pairs of nodes
Nov
14
answered Standard names and methods for this type of fitting minimization
Nov
14
comment Noncommutative version of Littlewood's First Principle
While the title sounds interesting to me, I have to admit that I don't have any idea what this "noncommutative setting" you are talking about may be, let alone what an analog of Littlewood's principle may be.
Nov
13
comment Does the boundary of a convex body contain a regular planar pentagon?
Does a convex body need to have nonempty other interior? Otherwise the answer is no.
Nov
12
revised Is the boundary $\partial S$ analogous to a derivative?
Corrected typos. Extended answer a bit.
Nov
9
comment Area of the minimal surface of a non-planar quadrilateral in 3d
Regarding your other comment: I thought 'minimal surface' would mean 'surface of minimal area' but probably there are some local minima (whatever this means in this context)?
Nov
9
comment Area of the minimal surface of a non-planar quadrilateral in 3d
A formula in elliptic functions or another non-elementary integral would be OK. In the end I would be happy with a simple numerical method to calculate the value.
Nov
7
asked Area of the minimal surface of a non-planar quadrilateral in 3d
Nov
5
reviewed Close How to solve the opposite of max flow problem?
Nov
4
reviewed Leave Open Difference Quotients Evans
Nov
4
reviewed Leave Closed Estimating a sum
Nov
4
answered Maximum of a mollified/convolution function
Nov
3
comment Maximum of a mollified/convolution function
Questions like this have been treated in the concept of "scale space methods" in mathematical image processing about 15 or 20 years ago where one was interested in the question: How many local minima and maxima survive after convolution and can new local minima or maxima be created? Unfortunately I forgot about the exact references but one result was along the lines: If you take a scale kernel $\phi_t(x) = 1/t\phi(x/t)$ and require that the number of local maxima and minima of $\phi_t\ast f$ is decaying with $t$, and some more hypotheses, then $\phi$ is a Gaussian…
Oct
31
reviewed Leave Closed A metric on $S^{2}$
Oct
30
comment numerical solver for stochastic optimal control problems
I think this is better suited for computational science over at scicomp.stackexchange.com.
Oct
29
comment Central-Slice-Theorem Analogue for Wavelet Transforms?
Why do you think that such analog should exist? The 2D Fourier transform and the 2D wavelet transform are not really similar things. You are aware of the fact that the wavelet transform results in a function that lives on a different set, right? Meanwhile, you may be interested in the ridgelet transform which combines the Radon and the wavelet transform.
Oct
29
awarded  Custodian
Oct
27
comment Anti-bidiagonal matrix with main anti-diagonal {1,2,3,…} and first sub-anti-diagonal {-1,-2,-3,…} has eigenvalues lambda={1,-2,3,-4,…}
Have you looked at the eigenvectors?
Oct
24
reviewed Leave Closed Is the ISC kaput
Oct
23
comment Are there examples of families of objects which are canonically isomorphic, but where diagrams of canonical isomorphisms don't commute?
In the first paragraph I thought that the unit square would be $[0,1]^2$ but then I realized that you had $[-1,1]^2$ in mind.