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Jan
19
awarded  Tumbleweed
Jan
12
revised Double mass analysis and statistical errors
added 46 characters in body
Jan
12
asked Double mass analysis and statistical errors
Aug
11
awarded  Yearling
Jul
2
awarded  Curious
Mar
25
asked Derivation of the advection equation
Mar
17
awarded  Popular Question
Aug
11
awarded  Yearling
Feb
28
revised Good metric on $C^k(0,1)$ and $C^\infty(0,1)$
added 193 characters in body
Feb
28
revised Good metric on $C^k(0,1)$ and $C^\infty(0,1)$
added 193 characters in body
Feb
28
answered Good metric on $C^k(0,1)$ and $C^\infty(0,1)$
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...
Feb
27
accepted Is every open, bounded and simply connected subset of $\mathbb{R}^n$ essentially a ball?
Feb
26
asked The simplicity of $\bigwedge^i \mathbb{C}^{n+1}$ as a representation of $\mathfrak{sl_{n+1}}$ and its weight vectors
Feb
19
accepted Do we really need Hahn-Banach that much?
Feb
19
comment Do we really need Hahn-Banach that much?
Okay, thank you! Makes me kind of sad, though... ;)
Feb
19
comment Do we really need Hahn-Banach that much?
Of course - didn't see that until now. That might prove a problem... :)
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 $\operatorname{sup}_X\le \operatorname{sup}_Y$.
Feb
19
revised Do we really need Hahn-Banach that much?
added 3 characters in body
Feb
19
asked Do we really need Hahn-Banach that much?