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May
25 |
comment |
Characterization of $l_p$ up to a linear isometry
@Mark Meckes: I think, this depends on the definition of facet. And I have no idea about $p\notin\{1,2,\infty\}$, I thought this must be digged up. |
May
25 |
revised |
Characterization of $l_p$ up to a linear isometry
specification |
May
25 |
comment |
Characterization of $l_p$ up to a linear isometry
For example, as far as I understand, the following statement is true: a Banach space $X$ is isometrically isomorphic to $\ell_1^n$, $n\in{\mathbb N}$, if and only if $\dim X=n$, and the unit ball of $X$ has exactly $2n$ extreme points. Is something similar true, say, for $\ell_\infty^n$? |
May
25 |
comment |
Characterization of $l_p$ up to a linear isometry
Bill, of course I mean another thing. The question is which geometric properties of (the unit ball in) a Banach space $X$ allow us to conclude that $X$ is isometrically isomorphic to $\ell_p^n$. And I don't ask about Hilbert spaces. |
May
25 |
comment |
Characterization of $l_p$ up to a linear isometry
Bill, this classification where is it described? And what is not clear in my question? |
May
25 |
asked | Characterization of $l_p$ up to a linear isometry |
May
23 |
comment |
What is a continuous path?
There was a little book by A.S.Parhomenko "What line is" (printed in 1954 in USSR). He gives the following definition of line with a reference to P.S.Urysohn: 1) a connected compact topological spaces is called continuum, 2) a continuum $C$ in $\mathbb R^2$ in called line, if for each point $x\in C$ and for each $\varepsilon>0$ there is a neighborhood $U$ of $x$ of diameter $<\varepsilon$ such that the boundary $\partial U$ of $U$ contains only singletons as continuums. |
May
22 |
comment |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
Hm... I had a hope that there is a paper that I can refer to... :) OK, Paul, thank you. |
May
21 |
comment |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
Marc Palm refers to a Harish-Chandra paper here mathoverflow.net/questions/162856/…. Paul, do you mean these results or something else? |
May
20 |
awarded | Nice Question |
May
20 |
revised |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
added 305 characters in body |
May
19 |
comment |
Fourier series of functions on compact groups
Marc, could you, please, advise reading about the case of $C^\infty$? |
May
18 |
comment |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
Ah, OK, thank you, I did it. |
May
18 |
comment |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
Yes, I think that there must (probably) be a tricky summation method like the Fejér one. |
May
18 |
comment |
Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series?
I gave the link to MSE. Or do you mean this link: mathoverflow.net/questions/162856/…? |
May
18 |
asked | Can a continuous function on a compact group $G$ be interpreted as the sum in $C(G)$ of its Fourier series? |
May
18 |
comment |
Fourier series of functions on compact groups
Is it possible that for continuous $f$ (and for arbitrary compact group $G$) the pointwise convergence can always be understood in some specific sense, like for example the Fejér theorem en.wikipedia.org/wiki/Fej%C3%A9r%27s_theorem suggests? |
Mar
29 |
asked | Uniform structure on the Banach bundle generated by a Banach module |
Jan
18 |
comment |
Is every distribution a linear combination of Dirac deltas?
A reference: W.Rudin, 6.26. |
Jan
17 |
revised |
What are your favorite concrete examples of limits or colimits that you would compute during lunch?
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