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| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 9 months |
| seen | May 13 at 13:01 | |
| stats | profile views | 90 |
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Feb 28 |
revised |
Good metric on $C^k(0,1)$ and $C^\infty(0,1)$ added 193 characters in body |
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Feb 28 |
revised |
Good metric on $C^k(0,1)$ and $C^\infty(0,1)$ added 193 characters in body |
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Feb 28 |
answered | Good metric on $C^k(0,1)$ and $C^\infty(0,1)$ |
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Feb 28 |
comment |
Good metric on $C^k(0,1)$ and $C^\infty(0,1)$ It is important to you that the interval your functions live on is open, right? If it would be closed like in $C^k([0,1])$, you could get a norm on this space that even makes it a Banach space. (And every norm induces a metric). That would be a rather good metric on $C^k([0,1])$ in my opinion. I don't know about the $C^{\infty}$-case though... |
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Feb 27 |
accepted | Is every open, bounded and simply connected subset of $\mathbb{R}^n$ essentially a ball? |
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Feb 26 |
asked | The simplicity of $\bigwedge^i \mathbb{C}^{n+1}$ as a representation of $\mathfrak{sl_{n+1}}$ and its weight vectors |
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Feb 19 |
accepted | Do we really need Hahn-Banach that much? |
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Feb 19 |
comment |
Do we really need Hahn-Banach that much? Okay, thank you! Makes me kind of sad, though... ;) |
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Feb 19 |
comment |
Do we really need Hahn-Banach that much? Of course - didn't see that until now. That might prove a problem... :) |
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Feb 19 |
comment |
Do we really need Hahn-Banach that much? Since every $x\in X$ can be written uniquely as $x=y+c$ for $y\in Y$ and $c\in C$, we have $\|y'(x)\|=\|y'(y)\|\le \operatorname{sup}_Y$, so $\operatorname{sup}_X\le \operatorname{sup}_Y$. |
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Feb 19 |
revised |
Do we really need Hahn-Banach that much? added 3 characters in body |
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Feb 19 |
asked | Do we really need Hahn-Banach that much? |
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Feb 14 |
accepted | Counterexample for the solvability of $-\Delta u = f$ for $f\in C^2$ |
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Feb 14 |
comment |
Counterexample for the solvability of $-\Delta u = f$ for $f\in C^2$ Thank you for pointing me to the problem. But isn't there a simpler counterexample? :) |
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Feb 14 |
asked | Counterexample for the solvability of $-\Delta u = f$ for $f\in C^2$ |
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Feb 13 |
comment |
Is every open, bounded and simply connected subset of $\mathbb{R}^n$ essentially a ball? Of coarse! Thank you :) |
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Feb 13 |
asked | Is every open, bounded and simply connected subset of $\mathbb{R}^n$ essentially a ball? |
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Feb 12 |
comment |
Is duality an exact functor on Banach spaces or Hilbert spaces? Awesome answer! Thanks, Martin and Nate! |
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Feb 12 |
accepted | Is duality an exact functor on Banach spaces or Hilbert spaces? |
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Feb 11 |
revised |
Is duality an exact functor on Banach spaces or Hilbert spaces? edited body |
