This question needs either one more reopen vote or one more delete vote. I am preferential to the "reopen" option, myself; the answers are good (I like the second one for pointing out that many different such mappings exist), and the question is tolerable enough I think it warrants keeping.

I did perform an edit that made the original close reason ("unclear") obsolete.

@anorton reopened

Thanks. In other news: today I learned about the "controversial edits" page in moderation tools... It's a great way to ruin my trust in 1.5k rep users submitting edits.

@Lord_Farin To improve the question, one possible way is to add the context or show effort. If the OP has posted something in comments, I can copy it from the comments to the question. The OP mentioned nothing in the comments so this was not a possibility.

The OP mentioned common denominator but they said they cannot proceed. This is possible thing which I could imagine as effort shown for a user at that level.

I do not have time to find examples, but I would say that it is not uncommon to make edits similar to mine. (But, ideally, the addition is something which the OP has said in comments or at least what can be inferred from they comments.)

Re: If you want it reopened, convince people under your own title, e.g. in a comment. I agree with the people that the question in that form was not good enough. So if I wanted it to reopened, the question had to be edited to get closer to the quality standards required by the site.

And everybody can click on revision history and see who made the edits.

As the question was delete, I found it improbable that they will try to improve the question and ask for undeletion. (Especially as it was an inexperienced users.)

This could show both to the OP and to the people discussing that particular question on meta that, in some situations, improving questions of other users is a reasonable thing to do.

If you feel strongly about it, you can revert my edits - I don't find it a good option, but I can promise you that I won't go into edit war.

I think that there were some posts on meta which are at least to some extent related to this. (But probably not questions asking explicitly about: When is it good thing to edit other users posts? Should it be explicitly stated that the edit was not by the OP?

So if you feel that this should be discussed more, there is also an option to make a post on meta.

TL;DR: All I have to say to defend myself is that I was trying to follow an approach to improving questions which has become relatively common on this site during the last year.

I agree with what Lord Farin and anorton that I should probably have left at least a comment under the post or write something in the edit summary.

BTW here is a comment from the meta along the same lines as the above discussion:

Let me just add that I was doing that with good intentions. (Despite the fact that I might have ended looking like a deceitful beep.)

[ SmokeDetector ] All-caps title: HELP WITH PROOF USING EPSILON-DELTA, PLEASE by ivivyy on math.stackexchange.com

@anorton I've retagged the question. (I don't thing sequences-and-series is a good fit there.) After the question has been reopened, there already has been a vote to close as off-topic.)

@MartinSleziak I wholeheartedly agree with such edits.

@MartinSleziak Improving questions is reasonable -- stronger, should be encouraged.

@MartinSleziak Fair enough, I trust you on that.

@SmokeDetector deleted by OP

@MartinSleziak This particular type of edit should display more or less clearly who has done what. But I feel that we're not too far apart any more. At least, not enough to warrant strong opinions over a small amount of edits as would arise from bringing this to meta.

@Lord_Farin Glad to hear that our opinion are not that different. (I value a lot both your and Gerry Myerson's contribution to the site. I would not feel good about starting an argument with either of you.)

I do not do this type of edits frequently. But in the future I'll try to indicate at least in the comment that the edit was not by OP.

Let me say that my initial reaction when this thing about "improving posts if you do not want to have you answers deleted" started was similar to yours.

I was somewhat hesitant. How can I do that? I cannot say what have the OP tried? (Well, unless they mentioned something in the comments or if I talked with them in chat.)

But, on the other hand, it might be better to judge questions by their content (and not by who edited the content in). If the question seems to be abandoned by the OP, then it is probably better if someone else edits the post, if this action might prevent some good answers being removed from the site.

I'll have to leave now. See you later!

@MartinSleziak See you.

@MartinSleziak Completely abandoned questions (e.g. where the user hasn't been seen in a long time) are fair game for complete rewriting, I would say. But perhaps that is something that could be discussed on meta.

nuke question about proof correctness

(Abbreviation for "close and delete", in case of mod involvement the first part is optional)