bio  website  regularize.wordpress.com 

location  Braunschweig, Germany  
age  37  
visits  member for  4 years, 11 months 
seen  3 hours ago  
stats  profile views  2,005 
Professor at TU Braunschweig.
Area: Inverse problems, regularization theory, applied functional analysis, mathematical image processing.
3h

comment 
What are your favorite instructional counterexamples?
@columbus8myhw The support is the closure of the set where the function is not zero. 
2d

reviewed  Leave Open Nonstandard numbers and exponential form of Zeta function 
2d

reviewed  Leave Open Solutions of an nonlinear evolution problem 
2d

reviewed  Approve Is $(X_G, d_G)$ , compact manifold? 
Aug
29 
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Convergence of FixedPoint Iteration of a dependent map
Have you looked at the properties of the corresponding iteration the product space? 
Aug
28 
reviewed  Close MLE of Gamma when only given observations 
Aug
24 
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Hyperfunctions supported at a point
Ha! Page 5 is not available in google books for me, this explains my ignorance… 
Aug
24 
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Hyperfunctions supported at a point
I don't know much about hyperfunctions but I am not sure what "coincide" should mean here. A distribution is an element in the dual of smooth functions with compact support while a hyperfunction is an equivalence class of holomorphic functionals. I do not see a canonical way to map one set into the other… E.g. how should a hyperfunction act on a smooth function and how to make such an identification that respects all wanted rules (such as the rules for the derivative…)? 
Aug
22 
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Construct a PDE solution from a net of approximations
@AlexM. I guess that your limit is something like "largest set in the partition goes to zero". Why not pick sequences of such converging partitions and show that limits are independent of the subsequences? 
Aug
22 
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Construct a PDE solution from a net of approximations
@IgorKhavkine This counterexample does not work with unique solutions (as requested by the OP or the edited question with explicit boundary conditions). 
Aug
22 
answered  Identities and inequalities in analysis and probability 
Aug
22 
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Identities and inequalities in analysis and probability
This is not widely known? 
Aug
22 
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Construct a PDE solution from a net of approximations
@IgorKhavkine I guess the difference is that the OP does not assume that $x_i$ converges to $x$ but only that $f(x)$ converges to zero and wants to conclude the convergence of the $x_i$. 
Aug
22 
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Construct a PDE solution from a net of approximations
I can't imagine a situation in which one naturally has a net of a solution of a PDE which is not a sequence. But maybe that's only my limited imagination… 
Aug
16 
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Looking for the name of a mathematical symbol that looks remotely like 1 (answer: indicator function)
In convex analysis the term indicator functions is used for a function that is zero in some set and plus infinity elsewhere. 
Aug
9 
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Do convolution and multiplication satisfy any nontrivial algebraic identities?
For the anonymous user: You misunderstood the (abused ) notation. The product there is the tensor product and not the point wise product. 
Jul
29 
awarded  Notable Question 
Jul
24 
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How to calculate $det(X^TX)$ efficiently, update one column of X each time
Not a good fit for this side  I suggest scicomp.stackexchange.com. Anyway: Why not do a factorization of $X_1$ (LU or QR) and down and update that? 
Jul
24 
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9point stencil “equivalent” for advection equation
This question should go well on scicomp.stackexchange.com. 
Jul
17 
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question about $TGV^2$ space
Added something on the interpretation with Radon measures… 