Timeline for Can we choose an element from a class?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
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| Mar 25, 2021 at 22:48 | history | edited | Ivan Feshchenko | CC BY-SA 4.0 |
edited body
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| Mar 25, 2021 at 17:53 | history | edited | Ivan Feshchenko | CC BY-SA 4.0 |
added 340 characters in body; edited tags
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| Mar 25, 2021 at 3:10 | history | became hot network question | |||
| Mar 25, 2021 at 0:06 | comment | added | Ivan Feshchenko | @NateEldredge Unfortunately, and this is the worst, is that I do not really understand if the function is needed here or not. | |
| Mar 24, 2021 at 22:21 | comment | added | Nate Eldredge | I think generically, the question is as follows? You have a first-order formula $\varphi(x,y)$, with $x,y$ free, and a set $A$ (maybe $A \subset \mathbb{R}$ here), and you can prove $\forall x \in A \: \exists y \: \varphi(x,y)$. You would like to conclude there exists a function $f : A \to B$, where $B$ is some set, such that $\varphi(a, f(a))$ for all $a \in A$. | |
| Mar 24, 2021 at 19:26 | answer | added | Asaf Karagila♦ | timeline score: 4 | |
| Mar 24, 2021 at 19:10 | history | asked | Ivan Feshchenko | CC BY-SA 4.0 |