3,109 reputation
1348
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years, 2 months
seen 2 hours ago

Professor at TU Braunschweig.

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


21h
awarded  Notable Question
2d
accepted Geometric measures different from Hausdorff
Nov
25
comment Continuous versions of tensors/ Tensors with infinite indices?
A situation where this works pretty straightforward is the case of functionals on $L^2$ (also on $L^p$ with $1<p<\infty$). There, the functionals are identified with functions, e.g. $(L^2)'=L^2$ and the tensor product of $L^2$ with itself is simple enough (en.wikipedia.org/wiki/Tensor_product_of_Hilbert_spaces).
Nov
25
comment Reference for a strong intermediate value theorem for measures
Actually, your statement is not strictly stronger than the result the OP is asking for since he wants the sets $S_t$ to be nested.
Nov
20
reviewed Leave Open “Almost” zeta function
Nov
19
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…
Nov
19
revised Removing constraints in convex optimization
Extended and corrected
Nov
19
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…
Nov
19
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 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
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?