Timeline for Can ZFC → NBG be iterated?
Current License: CC BY-SA 2.5
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 7, 2011 at 22:44 | vote | accept | Mike Shulman | ||
| Jan 6, 2011 at 20:44 | history | edited | Mike Shulman | CC BY-SA 2.5 |
clarify title
|
| Jan 6, 2011 at 3:19 | answer | added | Andrés E. Caicedo | timeline score: 17 | |
| Jan 6, 2011 at 1:05 | comment | added | Gerald Edgar | Maybe he means Grothendieck "universes"... | |
| Jan 5, 2011 at 23:47 | comment | added | Peter Krautzberger | Even though it's the opposite of an answer to your question, I thought it might be worthwhile to mention it as a comment. To go beyond classes one could build on Victoria Marshall's work jstor.org/stable/2274862. She starts from Bernay's theory of classes with a reflection principle. Unfortunately, her work is an anti-answer to your question -- the theories yield increasingly large cardinals... | |
| Jan 5, 2011 at 23:03 | comment | added | Theo Buehler | Feferman has some papers on that, together with a thorough discussion of foundations of category theory. They are accessible from math.stanford.edu/~feferman/papers.html In "Typical ambiguity ..." he shows that you can add a countable sequence of universes and still get a conservative extension of ZFC and in "Enriched stratified systems ..." he discusses some different approaches and also the relation to Morse-Kelley. | |
| Jan 5, 2011 at 22:55 | comment | added | arsmath | Do you have something in mind that would be different from Kelley-Morse set theory? | |
| Jan 5, 2011 at 22:44 | history | asked | Mike Shulman | CC BY-SA 2.5 |