Timeline for Does Cantor-Bernstein hold for classes?
Current License: CC BY-SA 2.5
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 6, 2010 at 21:09 | comment | added | Joel David Hamkins | I show the details of one way to do it in my answer. | |
| Sep 6, 2010 at 19:03 | comment | added | François G. Dorais | Could you expand your argument? I see that this works fine in MK (Morse-Kelley Set Theory), but I don't immediately see why it works in NBG. The problem is that NBG does not allow the comprehension of classes by quantification over classes, avoiding that seems non-trivial to me. | |
| Oct 19, 2009 at 10:56 | vote | accept | Philipp Lampe | ||
| Oct 19, 2009 at 1:41 | comment | added | Eric Wofsey | Sure it is. You can use the Schroder-Bernstein argument to explicitly construct a bijection from A to B given your two injections, for example. | |
| Oct 19, 2009 at 1:21 | comment | added | Philipp Lampe | Me either, but is that a proof? | |
| Oct 19, 2009 at 1:17 | history | answered | Eric Wofsey | CC BY-SA 2.5 |