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location Kleve, Germany
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visits member for 2 years, 4 months
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1h
comment Is there any multiplicative linear functional on B(H)?
Why is $P = V^*V$ and $Q = VV^*$ ?
1d
comment Prove the associative law for the addition of real numbers
If you may use that addition in $\mathbb Q$ is associative, this should be quite easy.
2d
revised Is is true $\forall_{A,B \subset X}: f(A - B)=f(A) - f(B)$?
edited body
Jan
23
answered Is is true $\forall_{A,B \subset X}: f(A - B)=f(A) - f(B)$?
Jan
18
comment CW approximation
Okay, and I guess it is then also not necessary to consider generators and one could instead attach cells for each representative of each class which is in consideration.
Jan
18
asked CW approximation
Jan
18
answered Norm of bounded real function
Jan
17
comment Definition of CW complex
Are the $\kappa_i$ embeddings ? We then could say $U \cap X^n$ is open iff $U \cap \kappa_n(X^n)$ is open, i.e. identify $X^n$ with its image under $\kappa_n$.
Jan
17
asked Definition of CW complex
Jan
13
comment Property of continuous functions regarding maximum
Claim 1 is true. Claim 2 clearly not. Just take indicator functions to get a counter example. By the way: A continuous function on a compact interval, as $[a,b]$ is, must also be bounded.
Jan
3
accepted $\mathbb RP^n$ as CW-complex
Jan
3
comment $\mathbb RP^n$ as CW-complex
Okay, thanks. I will think about that a bit more. This question is indeed answered. Feel free to post this as answer.
Jan
3
comment $\mathbb RP^n$ as CW-complex
Okay, that is strange :D I guess that is only true for $n =1$ ? For $n>1$ I do not really understand why attaching $D^n$ to $\mathbb RP^{n-1}$ via the quotient map gives $\mathbb RP^{n-1}$.
Jan
3
asked $\mathbb RP^n$ as CW-complex
Dec
23
accepted Compact open topology and nets
Dec
22
comment Compact open topology and nets
Some kind of explicit test to see wether a net converges or not. For example in the usual product topology of $Y^X$ a net converges if it converges pointwise.
Dec
21
asked Compact open topology and nets
Dec
9
awarded  Caucus
Dec
1
comment Solve this equation
What means $\langle E \rangle$ and $\langle N \rangle $ ?
Dec
1
answered Prove there exists a real number x such that