Timeline for Is $\text{Cont}(\mathbb{R},\mathbb{R})$ dense in $\mathbb{R}^\mathbb{R}$? [closed]
Current License: CC BY-SA 3.0
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Nov 23, 2017 at 17:54 | history | closed |
YCor Neil Strickland Jan-Christoph Schlage-Puchta user1073 Ramiro de la Vega |
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Nov 23, 2017 at 13:06 | comment | added | YCor | Additional exercise: there's a countable subset of $\mathrm{Cont}(\mathbf{R},\mathbf{R})$ that is dense in $\mathbf{R}^\mathbf{R}$. | |
Nov 23, 2017 at 12:37 | comment | added | YCor | "this argument" is indeed not well-written: it should be "a non-Borel self-map of $\mathbf{R}$ is not the pointwise limit of a sequence of continuous functions". This example shows that one has to be careful with dealing with limits in non-metrizable spaces, such as, typically, uncountable products. | |
Nov 23, 2017 at 11:25 | history | edited | Martin Sleziak | CC BY-SA 3.0 |
typo
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Nov 23, 2017 at 10:43 | review | Close votes | |||
Nov 23, 2017 at 17:54 | |||||
Nov 23, 2017 at 10:24 | vote | accept | Dominic van der Zypen | ||
Nov 23, 2017 at 10:18 | vote | accept | Dominic van der Zypen | ||
Nov 23, 2017 at 10:24 | |||||
Nov 23, 2017 at 10:05 | comment | added | Jochen Glueck | @Phil-W I think, this argument only shows that $\operatorname{Cont}(\mathbb{R},\mathbb{R})$ is not sequentially dense in $\mathbb{R}^{\mathbb{R}}$. | |
Nov 23, 2017 at 10:05 | answer | added | Taras Banakh | timeline score: 14 | |
Nov 23, 2017 at 10:03 | answer | added | Jochen Glueck | timeline score: 10 | |
Nov 23, 2017 at 9:54 | comment | added | Dominic van der Zypen | If you can elaborate on this a bit, you can post it as an answer and we can close this thread. | |
Nov 23, 2017 at 9:51 | comment | added | Phil-W | I would say no, since a non Borel self-map of $\mathbb{R}$ is not the limit by pointwise convergence of continuous functions. | |
Nov 23, 2017 at 9:33 | history | asked | Dominic van der Zypen | CC BY-SA 3.0 |