3,092 reputation
1248
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years, 1 month
seen 13 hours ago

Professor at TU Braunschweig.

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


18h
comment Minimal surface dividing a simply connected region into two regions of equal volume
possible duplicate of Minimal surface which divides a convex body into two regions of equal volume, I don't see how this question differs from the one you linked.
1d
reviewed Leave Open “Almost” zeta function
2d
comment Removing constraints in convex optimization
Well, ehm, actually I don't see it either… Adapted my answer which is only a "partial answer" now…
2d
revised Removing constraints in convex optimization
Extended and corrected
2d
comment What's the idea behind various equivalent norms on Besov spaces $B^{s}_{p,q}$?
Another book that is quite detailed is Runst and Sickel's Sobolev Spaces of Fractional Order, Nemytskij Operators, and Nonlinear Partial Differential Equations. However, I guess for the equivalence of the norms they refer to Triebel…
2d
comment Geometric measures different from Hausdorff
Thanks a lot for the answer, especially for pointin to Frostman's lemma, densities and the example where $H^m(A)>0$ and $G_m(A) = 0$. This is exactly in the direction I was hoping. If you had additonally some concrete examples where Hausdorff, Dyadic and Spherical Measure differ I would accept and cash the bounty right away!
Nov
18
reviewed Close measures of global stability
Nov
18
reviewed Leave Open How to prove that a kernel is positive definite?
Nov
17
answered Removing constraints in convex optimization
Nov
14
reviewed Approve suggested edit on Graph automorphism that swaps two pairs of nodes
Nov
14
reviewed Leave Open RIP, NSP and Spark of A Matrix
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
11
comment RIP, NSP and Spark of A Matrix
Hint: the NSP does not change if you scale the columns of the matrix but the RIP constant can go to zero under scaling.
Nov
11
comment RIP, NSP and Spark of A Matrix
All these notions arise in compressed sensing (hence the tag).
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