3,553 reputation
12051
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years, 10 months
seen Jul 29 at 8:47

Professor at TU Braunschweig.

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


May
6
answered Examples of common false beliefs in mathematics
Apr
24
reviewed Approve Embedding Theorem for topological spaces, and in general
Apr
23
comment l1 Quadratic Programming
Noting that the above problem has all these guys as variables: Isn't that in standard for already?
Apr
23
comment A question involving Mazur's Lemma
Well, the degenerate case $y_n = x_n$ does not work so some assumption on the convex combination is needed.
Apr
21
reviewed Reopen Decomposition space of $\mathbb{C}$ by concentric circles
Apr
20
awarded  Good Answer
Apr
14
revised Is there a classification of 2d extended TQFTs with defects?
spelled out TQFT and added link
Apr
14
comment 2, 3, and 4 (a possible fixed point result ?)
As far as I understood, the BGK (Browder-Göhde/Göbel-Kirk) fixed point theorem states that every non-expansive self-mapping on a non-empty, closed and convex subset of a uniformly convex Banach space has a fixed point.
Apr
7
awarded  Necromancer
Mar
27
comment Hadamard / matrix product adjoint
Ok, I see now. I think a better fit for this question would be scicomp.stackexchange.com. Anyway: The adjoint is defined by $\langle A^* y,x\rangle = \langle y,Ax\rangle$. You do adjoints one by one from outside to inside.
Mar
26
comment Hadamard / matrix product adjoint
Sorry, but this does not make sense. What is the Hadamard product of the matrix S and the vector Fx?
Mar
26
comment Hadamard / matrix product adjoint
Err... So x is a matrix?
Mar
26
comment Hadamard / matrix product adjoint
I could not parse your definition of the operator A. If D and S are matrices, do you build the Hadamard product with the matrix of the Fourier transform?
Mar
26
comment Convergence in energy of bounded (semi)subharmonic functions
Sorry for the late reply: I guess the best thing would be to write an answer yourself so that this is kept for the records.
Mar
26
reviewed Approve Are all rational exactly solvable differential equations known?
Mar
24
awarded  Nice Answer
Mar
24
reviewed Leave Open Which way for reading the proofs?
Mar
24
answered Which way for reading the proofs?
Mar
23
reviewed Leave Closed If a polynomial $p(z)$ omits a value, then $p(z)-\dfrac{(1-e^{i\psi})}{n}zp^{\prime}(z)$ also omits that value
Mar
23
reviewed Leave Open Analysis of Sobolev spaces