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visits | member for | 4 years, 6 months |
seen | 2 hours ago | |
stats | profile views | 1,566 |
Aug 22 |
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A question about cardinal numbers when the Axiom of Choice is absent
Many thanks, Asaf, for your response. I am amazed because I was sure the answer would be "No". |
Aug 21 |
asked | A question about cardinal numbers when the Axiom of Choice is absent |
Aug 17 |
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A question about ordinal numbers and sub-theories of ZF
Thanks for the information |
Aug 15 |
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Two questions about convex subsets of Hilbert Space
Many thanks, Christian, for this information. |
Aug 15 |
accepted | Two questions about convex subsets of Hilbert Space |
Aug 15 |
asked | Two questions about convex subsets of Hilbert Space |
Aug 15 |
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A question about ordinal numbers and sub-theories of ZF
What does "close (2)" mean? Is this question closed out? It is a rather "fuzzy" question and I can understand why some would vote to close it. Prior to asking this question, I had asked 99 questions on "mathoverflow.net". Why is the total number of my questions still listed as 99-instead of a larger number. |
Aug 14 |
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A question about ordinal numbers and sub-theories of ZF
Andreas, you are right. But what I am asking is, which of the axioms of ZF are actually needed to prove the existence of a all the sets which satisfy von Neumann's formula defining wjch sets are ordinal numbers and which belong to the set theoretic hierarchy of ZF. |
Aug 13 |
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A question about ordinal numbers and sub-theories of ZF
@Andreas: Levy showed that there existed no formula A(x) in the language of ZF, containing x as its one and only free variable, which expressed the statement "x is a Cardinal Number". Ordinal numbers are defined by such formulae in ZF and it is then proved in ZF that sets satisfying these definitions exist. I am asking whether all the axioms of ZF are needed to carry out these proofs. |
Aug 12 |
asked | A question about ordinal numbers and sub-theories of ZF |
Jul 28 |
awarded | Popular Question |
Jul 8 |
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One or two questions about so-called “absolute” set theories
"Absolute" set theory (or theories) are defined and discussed on pages 79-80 of the book "Foundations of Mathematics: Symposium Papers Commemorating the Sixtieth Birthday of Kurt Godel" which was published in 1969 by Springer Verlag. The article by Takeuti entitled "The Universe of Set Theory" appears on pages 74-128 of this book. After defining "absolute" set theories, Takeuti does not say much more about them in this article. That is why I am asking whether there has been any further work in tis area. |
Jul 6 |
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Can a “weak” topological space be a Moore space?
@Christian Remling: Many thanks for your response. Since the space l^2 is separable, it seems that if we take B to be l^2, then the anmswer to my question is "YES". |
Jul 6 |
asked | One or two questions about so-called “absolute” set theories |
Jul 6 |
awarded | Notable Question |
Jul 5 |
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Can a “weak” topological space be a Moore space?
A Moore space is a regular, Hausdorff developable topological space |
Jul 4 |
asked | Can a “weak” topological space be a Moore space? |
Jul 2 |
awarded | Inquisitive |
Jul 2 |
awarded | Curious |
Jun 16 |
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A question about “local” versus “global” large cardinal axioms
@ Joel: Many thanks for your answer. It seems then that the least cardinal satisfying any global property can never be less than the least cardinal satisfying any local property. |