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Martin Sleziak
Martin Sleziak
4:40 AM
@YCor I do not think that tags on deleted questions matter that much. (Undeleting would lead to creation of the tag (again), but the question is unlikely to get undeleted.)
I am below 10k on MO, so I cannot actually see the deleted question - so I did not know who posted it.
 
 
3 hours later…
YCor
YCor
7:41 AM
@MartinSleziak I think a deleted (non-locked) question or answer can be edited without being undeleted.
 
Martin Sleziak
Martin Sleziak
Yes, I know that.
To be more specific:
A deleted question can be edited by others.
There are some restrictions when the OP can edit deleted question.
IIRC if it is self-deleted question the OP cannot edit it. (To prevent abuse - for example, somebody could edit spam into the question and after undeleting, the spam link could go unnoticed, since undeleting does not bump the post.)
But I think there isn't similar restriction to answers.
@YCor I suppose you mentioned this in connection with removing the tag from the deleted question.
Yes, you can certainly do that. (I cannot do that - on MO I do not see deleted post.)
When I wrote the above message ("I do not think that tags on...") what I meant was that how the deleted question is tagged would only influence the list of tags on the site if it is again undeleted.
I do sometimes edit tags, typos, other things also in deleted posts on Mathematics. But I am fully aware that such edits are less important - since most people do not see the post anyway, the edit becomes more useful only in case when the post is again undeleted.
 
YCor
YCor
8:13 AM
@MartinSleziak thanks for these details. I removed the tag from both questions, finally. By the way, I also removed the tag analytic-geometry from the deleted question.
 
 
4 hours later…
Martin Sleziak
Martin Sleziak
12:25 PM
11
Q: An easy proof of the uncountability of bijections on natural numbers?

Abhishek ParabThe proof that I have in mind is as follows - $\text{Gal }(\overline{\mathbb Q}/\mathbb Q)$ is a proper uncountable subgroup of the group of permutations on countably many symbols, hence the latter is uncountable. . But it needs a lot of jargon from topology and algebra. Is there a neat proof ...

set-theory
18
Q: Cardinality of the permutations of an infinite set

Roy MacleanIf you have an infinite set X of cardinality k, then what is the cardinality of Sym(X) - the group of permutations of X ?

set-theory
 
 
2 hours later…
YCor
YCor
2:06 PM
@MartinSleziak I think symmetric-group fits, and maybe also gr.group-theory. These questions from 2010 would be probably closed as off-topic now.
 
Martin Sleziak
Martin Sleziak
2:25 PM
TBH, I'd say that MO folk was never too consistent about what is and what isn't allowed on the site. So it's difficult to say what would be closed.
Probably whether the question is interesting for MO users is more important whether it actually is a research-level question.
I think I have quoted this a few times:
in MathOverflow, Oct 3 '17 at 19:05, by Todd Trimble
I think one of the main criteria for "success" at MO is whether the users find a question interesting or challenging; that in itself serves as "self-motivating". Thus lack of an explicit motivation or setting of context is often seen as forgivable, if the question is perceived as having apparent intrinsic interest already.
 

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