Timeline for Shortest axiom of infinity for foundationless set theory
Current License: CC BY-SA 4.0
20 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 13, 2020 at 22:10 | comment | added | Wlod AA | @user76284, you're too kind, thank you! | |
| Apr 13, 2020 at 18:53 | vote | accept | user76284 | ||
| Apr 13, 2020 at 18:53 | comment | added | user76284 | This is slightly longer than the one in my question but I'll accept it :) | |
| S Mar 25, 2020 at 13:56 | history | suggested | user76284 | CC BY-SA 4.0 |
Moved $\exists a$ inside the conjunct
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| Mar 25, 2020 at 0:05 | comment | added | Wlod AA | @user76284, u'r right, now the distance between the symbols to be associated is shorter (local formula understanding is easier than global). I don't see the edit yet, I hope that it will show up soon when admins have time to look at it. | |
| Mar 24, 2020 at 23:40 | comment | added | user76284 | I moved $\exists a$ inside the conjunct. This doesn't change the length of the formula but it does make it a bit clearer, I think. | |
| Mar 24, 2020 at 23:40 | review | Suggested edits | |||
| S Mar 25, 2020 at 13:56 | |||||
| Mar 24, 2020 at 23:36 | comment | added | Wlod AA | @user76284, oh, yes! That's why I was/am uneasy about this game, I don't know the formal rules. (On the other hand, this kind of optimizing formulas are attractive to me anyway). | |
| Mar 24, 2020 at 23:31 | comment | added | user76284 | Wouldn't the resulting formula be longer in the internal language, since you have to say $\exists a (a \in b \land \neg \exists c (c \in a))$ rather than just $\exists a (a \in b)$? | |
| Mar 24, 2020 at 23:27 | comment | added | Wlod AA | @user76284, first of all, thank you for your edit. I could remove $\ \exists_a\ $ and replace $\ a\in b\ $ by $\ \emptyset\in b.\ $ In general, in the context of the OP Question (nothing wrong about it!) I felt uncomfortable and extra defensive about my formula. I am not a logician hence I don't know the customs, habits, ... to be obeyed in a thread as this. | |
| Mar 24, 2020 at 23:20 | comment | added | user76284 | Can't $\exists a$ be moved inside to capture just $a \in b$? | |
| Mar 24, 2020 at 23:19 | comment | added | user76284 | You mean in the external language? | |
| Mar 24, 2020 at 7:04 | comment | added | Wlod AA | If $\ \emptyset\ $ is legal then I can save 2 characters. | |
| S Mar 24, 2020 at 3:23 | history | suggested | user76284 | CC BY-SA 4.0 |
Abbreviation
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| Mar 24, 2020 at 0:29 | review | Suggested edits | |||
| S Mar 24, 2020 at 3:23 | |||||
| Mar 22, 2020 at 21:24 | comment | added | Wlod AA | @EmilJeřábek, thank you. (I was fighting non-existing logical dragons). | |
| Mar 22, 2020 at 11:06 | history | edited | Emil Jeřábek | CC BY-SA 4.0 |
Further simplified, using extensionality
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| Mar 22, 2020 at 10:50 | history | edited | Emil Jeřábek | CC BY-SA 4.0 |
Removed needless S's (elements of sets are sets by heredity). Fixed formatting.
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| Mar 20, 2020 at 6:51 | history | edited | Wlod AA | CC BY-SA 4.0 |
statement statement stated
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| Mar 20, 2020 at 6:13 | history | answered | Wlod AA | CC BY-SA 4.0 |