Timeline for Counterexample for the Open Mapping Theorem
Current License: CC BY-SA 2.5
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 6, 2010 at 2:49 | comment | added | Bill Johnson | Oh, yes, Pietro; that is simpler. | |
| Nov 4, 2010 at 21:37 | comment | added | Pietro Majer | Yes, that's very nice, I didn't notice before either. In fact, it's a neighborhood of zero because it's a barrel in a Banach space. | |
| Nov 4, 2010 at 13:19 | comment | added | Bill Johnson | True, Andreas, but I learned something thinking about this standard problem not in a course environment: Notice that my solution shows that the absolutely closed convex hull of any Hamel basis for a Banach space contains a neighborhood of zero. Did you know this? I certainly did not. | |
| Nov 4, 2010 at 9:01 | comment | added | Pietro Majer | I wonder if there is an example without using AC. | |
| Nov 4, 2010 at 7:16 | comment | added | Andreas Thom | I voted to close, since this question does not seem to be a question on a research level. It is almost perfectly suited for Math Stack Exchange (I think), since the basic tools to find the required example (like a Hamel basis, the existence of unbonded linear functionals etc.) are sufficient. In some sense it is an exercise everybody should solve, but not get solved within one hour on MO. I am sure that a crowd of interested students would have been able to answer this question quickly. | |
| Nov 3, 2010 at 22:35 | answer | added | Pietro Majer | timeline score: 15 | |
| Nov 3, 2010 at 21:29 | answer | added | Bill Johnson | timeline score: 10 | |
| Nov 3, 2010 at 21:25 | answer | added | Nate Eldredge | timeline score: 6 | |
| Nov 3, 2010 at 21:15 | answer | added | Pietro Majer | timeline score: 7 | |
| Nov 3, 2010 at 20:55 | vote | accept | Minh | ||
| Nov 3, 2010 at 20:54 | vote | accept | Minh | ||
| Nov 3, 2010 at 20:55 | |||||
| Nov 3, 2010 at 20:11 | history | edited | Andrey Rekalo | CC BY-SA 2.5 |
Texified, tag added
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| Nov 3, 2010 at 19:58 | history | asked | Minh | CC BY-SA 2.5 |