3,553 reputation
11951
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years, 10 months
seen 6 hours ago

Professor at TU Braunschweig.

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


Jan
22
reviewed Leave Open About a completion of a Sobolev space
Jan
15
reviewed Leave Closed For which rational values of $c$ and $d$ are the numbers $\sin{(\pi\cdot c)}$, $\sin{(\pi\cdot d)}$ and $1$ linearly dependent over $\mathbb{Q}$?
Jan
15
reviewed Leave Open BDF2 and TR-BDF2: what is better?
Jan
13
reviewed Approve How to find the generic initial ideal?
Jan
13
reviewed Leave Open What is the idea behind interpolation spaces?
Jan
13
reviewed Leave Open Solution of a linearly constrained quadratic programming problem
Jan
13
reviewed Leave Open Getting a measure from a premeasure through an adjoint
Jan
13
reviewed Edit How to find the generic initial ideal?
Jan
13
revised How to find the generic initial ideal?
format edited
Jan
9
comment Are there any with Erdös number 1 on mathoverflow?
Evidence: "Coloring graphs with locally few colors" by P. Erdõs, Z. Füredi, A. Hajnal, P. Komjáth, V. Rödl, Á. Seress, Discrete Math., 59(1986), cs.elte.hu/~kope/localcoloring.pdf
Jan
4
comment distribution discretization
I suspect that you will not have approximation in the total variation distance but only weak approximation. Probably this can be quantified by Prokhorov or Wasserstein metrics but I don't know a good pointer...
Jan
4
revised Does removing some constraints in convex program change the optimal solution?
added 98 characters in body
Jan
4
comment Does removing some constraints in convex program change the optimal solution?
Jupp, this is also true in two variables.
Jan
4
answered Does removing some constraints in convex program change the optimal solution?
Dec
29
comment Finding sparsest solution of a linear system
Some good heuristics go under the name "pursuit", e.g. (regularized) (orthogonal) matching pursuit or basis pursuit.
Dec
26
comment An inequality concerning restricted isometry property
If you only have $supp(x) \subset S_1$ and $supp(y) \subset S_2$ then no lower bound greater than zero is to be expected and even if you have non-trivial intersection of the supports then the inner product can well be zero, I guess.
Dec
21
comment Open problems in compressed sensing
One thing is that it makes a huge difference if one answers this question as a mathematician or as an engineer. Well, of course this is site for mathematics but the idea of compressed sensing is really a practical one: get information about a high dimensional object that lives in lower dimensional but nonlinear subspace from few measurements. The meaning of all ingredients is debatable here and varies a lot from problem to problem. Hence one open problem is to find the right mathematical formulation of the problem...
Dec
19
comment Image of (right) inverse trace map $\xi\colon H^{\frac 12}(\partial\Omega) \to H^1(\Omega)$ dense in $H^1(\Omega)$?
Ok, right - I thought that I had a basic misconception about the problem…
Dec
19
comment journal to submit mathematic books' review
The German "Mathematische Semesterberichte" publishes such reviews (probably only in German).
Dec
19
reviewed Close How to construct a graph with arbitrarily large girth and large chromatic number?