bio  website  regularize.wordpress.com 

location  Braunschweig, Germany  
age  36  
visits  member for  3 years, 11 months 
seen  12 mins ago  
stats  profile views  1,658 
Professor at TU Braunschweig.
Area: Inverse problems, regularization theory, applied functional analysis, mathematical image processing.
2h

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Are there any references for the measures without any growing tails?
So now the question is: For what measures $\mu$ does $\mu * f \in L^\infty$ hold, right? 
1d

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numerical method (implicit) for nonlinear pde
What is the question here? 
Sep 12 
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How does the distribution of Erdős number evolve over time ? How to build a model to fit the real data ?
I suspect that the assumption that the Nummer of new articles and mathematicians is constant is false and guess that both grow superlinearly if not exponentially (at least for the next few years  eventually it may be logistical growth...). 
Sep 11 
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Checking the intersection of two sets
Of course, you could also use @EmilJeřábek's formulation and use the constraints $l\leq Xy\leq u$. 
Sep 11 
answered  Checking the intersection of two sets 
Sep 11 
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Checking the intersection of two sets
This is a convex feasibility problem and could be solved, e.g. by alternating projections. 
Sep 8 
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“Paradoxes” in $\mathbb{R}^n$
The unit ball is indeed a special convex body. 
Aug 14 
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Heuristic interpretation of the 'third index' for Besov and TriebelLizorkin spaces
That's all well but I don't get a heuristic interpretation of $q$ out of it. Sure, the embeddings are clear but in what sense is $q$ some "fine tuning"? Probably the case $q=\infty$ is interesting: Although the spaces $B^s_{p,\infty}$ are not Sobolev spaces one somehow sees a link to Sobolev regularity. Do you know an example of a function in $B^s_{p,\infty}$ that does not lie in $B^s_{p,p}$? Maybe for $p=2$? 
Aug 14 
revised 
Heuristic interpretation of the 'third index' for Besov and TriebelLizorkin spaces
only fixed umlauts 
Aug 13 
reviewed  Reject suggested edit on Matching number and chromatic number 
Aug 1 
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Finding gradient of an optimization
You optimize over a binary variable (which seems to be a binary matrix, right?)? And you want the gradient of the objective with respect to this binary variable $w$? Better relax to $w_{ij}\in[0,1]$ or so. Also: What do you mean by "but for $T(t_i,w)$ is changing in each time step"? 
Jul 30 
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Spectral multipliers visavis Differential geometry
Sorry but I don't really get the last motivating questions. Do you say that you would be satisfied by an answer like "Somebody else uses this stuff for something."? But probably this is just my ignorance for the works you point to. 
Jul 26 
awarded  Nice Answer 
Jul 25 
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Intuition for Integral Transforms
See also the first chapter of "A guide to distribution theory and Fourier transforms" by Strichartz. 
Jul 25 
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Decomposition of an integral operator into a composition
I heard that the chebfun2 package for MATLAB can perform some kind of LU decomposition for functions defined on the unit square… 
Jul 25 
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Intuition for Integral Transforms
(cont) and this is "testing against a characteristic function". Well, that does not fit perfectly to test functions since these are $C^\infty$ but well  the physical world tends to be a bit fuzzy anyway… 
Jul 25 
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Intuition for Integral Transforms
@TomCopeland I thought that "testing against a function" has a meaning in a physical sense. Consider the quantity you would like to test as some physical quantity, e.g. the temperature distribution in your office or the sugar concentration in your cup of tea. What should you do if you would like to know the value of this at a certain point? [In mathematical terms: do point evaluation.] As a physicist you realize that can't do perform this kind of "test". But what you can do, is to evaluate some kind of "average" (e.g. by taking out some sample of tea with a pipette) (to be continued) 
Jul 24 
revised 
Both NPhard but different
corrected spelling, expanded tsp 
Jul 24 
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Proximal operator of modified L1 matrix norm
There are simple rules for the prox of translations (just do substitution in the minimization problem). For the last case I only expect a simple solution for invertable $M$ (again substitute). 
Jul 24 
answered  Examples of famous 'workhorse' theorems 