3 ms·
> the unnameable reals, which are almost every real Is there a definition you have in mind for "unnameable"? If you mean definable [0][1], then this is indepen
by scapp 4y ago
> the unnameable reals, which are almost every real
Is there a definition you have in mind for "unnameable"? If you mean definable [0][1], then this is independent of ZFC.
The "standard" argument for this is flawed, and indeed there are models where every real is definable. [2]
[0] "x is definable if there exists a first order formula with one free variable P such that x is the unique real number with P(x) true"
[1] https://en.wikipedia.org/wiki/Definable_real_number#Definability_in_models_of_ZFC https://en.wikipedia.org/wiki/Definable_real_number#Definabi...
[2] https://mathoverflow.net/questions/44102/is-the-analysis-as-taught-in-universities-in-fact-the-analysis-of-definable-numb/44129#44129 https://mathoverflow.net/questions/44102/is-the-analysis-as-...
- floxy 4y agoMaybe the GP is referring to something like Chapter 5 of Chaitin's Meta Math!. https://arxiv.org/pdf/math/0404335.pdf https://arxiv.org/pdf/math/0404335.pdf