3,037 reputation
1247
bio website regularize.wordpress.com
location Braunschweig, Germany
age 36
visits member for 4 years
seen 1 hour ago

Professor at TU Braunschweig.

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


Jul
16
comment Metrization of weak convergence of signed measures
Sorry for longer quietness, but may I ask what problems do arise with this metric if the measures are signed? I thought that the constraint $|f(\omega)|\leq 1$ would take care of these. In the metric we use differences of measures anyway so what goes in the norm is generall signed.
Jul
16
reviewed Approve suggested edit on Sum over growing Young tableaux
Jul
16
accepted Is the prox-residual monotone?
Jul
16
comment Is the prox-residual monotone?
Great, thanks! Somehow, my examples where either somehow isotropic or random and did not show this behavior.
Jul
15
asked Is the prox-residual monotone?
Jul
15
asked Geometric measures different from Hausdorff
Jul
14
awarded  Nice Question
Jul
12
comment Heuristic interpretation of the 'third index' for Besov and Triebel-Lizorkin spaces
Finally somebody asked this here! (I wonder why I did not…)
Jul
5
reviewed Approve suggested edit on What is natural about the well-known bijection between conjugacy classes and irreps of a symmetric group?
Jul
4
answered Mathematicians who made important contributions outside their own field?
Jul
2
awarded  Curious
Jun
26
answered Relativistic Control Theory
Jun
19
answered Discrete gradient on point clouds
Jun
17
answered Roots of modified polynomials
Jun
15
comment Why are polynomials so useful in mathematics?
I would phrase the first reason for the usefulness of quadratics as "They imply a notion of positivity".
Jun
15
comment Why are polynomials so useful in mathematics?
Polynomials are so useful because they approximate analytic functions so well.
Jun
10
comment Necessity of coercivity assumption in Minty's theorem
Are you sure that your definition of coercive is correct? (There are different definitions around - what you call coercive is also known as "strongly coercive".) Which this definition, coercivity is not necessary ($x\mapsto \sqrt[3]{x}$). I known the theorem with the condition that $\langle f(x),x\rangle/\|x\|\to\infty$…
Jun
5
comment How many facets can $\{\|D^T x\|_1\leq 1\}$ have?
In dimension two I couldn't get more than $2p$ facets. But that does not answer your question… But wait: What do you mean by combinatorial type?
Jun
5
comment How many facets can $\{\|D^T x\|_1\leq 1\}$ have?
@eins6180: Not quite. I am especially interested in the scaling in $p$ and the one constraint $\|D^Tx\|_1\leq 1$ can be formulated as $2^p$ inequalities (doing case distinction over the absolute values in the the sum). However, in the construction I did usually many of these inequalities are inactive… I also guessed that this problem may be hard but had the hope that the special construction of the polytope as a kind of distorted one-norm would make the problem simpler…
Jun
5
comment Is this statement which relates the Fourier transform of a function to its singularities correct?
I found the formulation of $x_t$ and $y_t$ a bit confusing. Similarly to Brendan Murphy suggestion, I think a more appropriate formulation would be to use complex coordinates and investigate the function $\omega \mapsto \int_0^\omega \hat f(\Omega)\exp(t\Omega) d\Omega$ (the real and imaginary part of this are $X_t$ and $y_t$.