Timeline for A set for which it is hard to determine whether or not it is countable.
Current License: CC BY-SA 2.5
20 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 13 at 0:09 | comment | added | Lucenaposition | What about $L\cap\mathcal{P}(\omega)$? Its cardinality is $\omega_1^L$ which is uncountable assuming $V=L$ but countable assuming a measurable cardinal exists (or $0^\text{#}$ exists) | |
| Mar 23, 2011 at 19:21 | answer | added | P C | timeline score: 0 | |
| Mar 22, 2011 at 16:53 | answer | added | David E Speyer | timeline score: 11 | |
| Mar 22, 2011 at 14:51 | answer | added | Ashutosh | timeline score: 4 | |
| Mar 22, 2011 at 13:54 | comment | added | mathahada | Maybe you should change it to "sets for which it is hard to guess their cardinality"? Then there's room for other nice questions like the cardinality of the set of all continuous real valued functions (this example is not difficult, though, but maybe there are others in this vain) | |
| Mar 22, 2011 at 13:40 | answer | added | Keivan Karai | timeline score: 10 | |
| Mar 22, 2011 at 12:55 | answer | added | Tony Huynh | timeline score: 13 | |
| Mar 22, 2011 at 12:44 | answer | added | Pete L. Clark | timeline score: 11 | |
| Mar 22, 2011 at 11:09 | comment | added | Zsbán Ambrus | Are you only interested in sets that are obviously infinite? If not, I guess you can give definitions that define sets that are either empty or very large. | |
| Mar 22, 2011 at 10:09 | answer | added | mathahada | timeline score: 5 | |
| Mar 22, 2011 at 5:17 | answer | added | Syang Chen | timeline score: 7 | |
| Mar 22, 2011 at 3:30 | answer | added | Daniel Litt | timeline score: 23 | |
| Mar 22, 2011 at 3:19 | answer | added | fedja | timeline score: 20 | |
| Mar 22, 2011 at 3:06 | answer | added | ndkrempel | timeline score: 4 | |
| Mar 22, 2011 at 2:14 | answer | added | Bjørn Kjos-Hanssen | timeline score: 14 | |
| Mar 22, 2011 at 1:03 | answer | added | Qiaochu Yuan | timeline score: 2 | |
| Mar 22, 2011 at 0:24 | comment | added | Gerald Edgar | Strong measure zero set... mathoverflow.net/questions/48453/… | |
| Mar 21, 2011 at 23:59 | history | made wiki | Post Made Community Wiki by Spencer | ||
| Mar 21, 2011 at 23:53 | answer | added | Matthew Kahle | timeline score: 18 | |
| Mar 21, 2011 at 23:23 | history | asked | Spencer | CC BY-SA 2.5 |