on improving another's question

robjohn

May 30, 2019 04:59

@YuiToCheng If a question is poorly stated, we are encouraged to improve it. I see no reason not to improve the "initial question" to make it a better question. That would seem to benefit the site. However, the improvements to the question were removed and now it is closed and on the path to deletion.

The question, as amended to include an asymptotic expansion, is more interesting than the question whose answer is 0. Why revert it to the original question? That seems to concentrate on the OP, not the question itself.

Thinking about that question lead me to make some interesting discoveries, and I think allowed me to write a good answer.

YuiTo Cheng

May 30, 2019 06:04

@robjohn I have no problem with your amendment. However, I would rather support a newly asked question, that better models a good question, which you can copy and paste your earlier answer into. That will be a great example of self-answering!

user21820

May 30, 2019 14:19

@robjohn Please show me evidence that the asker gave in comments the integral obtained via the substitution. Otherwise it deserves to be deleted in my opinion (and so the closure reason is irrelevant to me). Thanks.

robjohn

May 30, 2019 14:57

@user21820 so you're saying that if the improvement does not come from the OP, then the question deserves to be closed/deleted? There were many times when I claimed a question was interesting, but there was simply too little context, and I was told to add context (I believe it was by amWhy, but that is not important). That is what I've tried to do in several cases recently, all of which have met the same response: the OP didn't improve the question, so it doesn't count.

user21820

@robjohn You claimed "the OP discussed their attempts in comments". So I ask for evidence. If you can't provide evidence, then please don't make such a claim.

robjohn

@user21820 They mentioned the substitution, but they didn't write out the integral. However, that is beside the point of my comment: if the improvement doesn't come from the OP, it doesn't count.

I am not trying to get that question undeleted necessarily, but to get a handle on how things are perceived here.

user21820

@robjohn I will tell you my viewpoint, but you'd have to ask the others for theirs, because some have stricter criteria and some have looser criteria. I firmly believe in not putting words into anyone's mouth. This excludes correcting typos/grammar or obvious careless errors in answers, but includes the kind of edit that you made.

In this specific example, how do we know that the asker didn't just copy a hint that said "use substitution t=ln(x)"? We don't. Likewise we have no evidence that the asker actually tried the substitution and did it correctly, since there is no working and not even the result of substitution.

However, I make no distinction between context in the question written by the asker and context in comments by the asker, though I would advise the asker to edit the question instead of just writing comments. Sometimes I edit for them to transfer their comments verbatim.

At the same time, this issue of putting-words-in-mouth is orthogonal to the issue of whether a question is bad. I want to see clear evidence of genuine effort by the asker or the motivation behind the question, and that for me is enough for a question not to be closed. In the absence of both, I think it is a bad question and should be closed.

Furthermore, if a bad question does not have any intrinsic mathematical interest or does not have an excellent answer like this, then I think it should be deleted.

robjohn

May 30, 2019 15:16

@user21820 Thank you for your viewpoint. I think that a change to a question that improves the site, whether added by the OP or someone else, is valid. It's more about the quality of the site than a few points that might b gotten by the OP.

user21820

@robjohn My goal is not infinitesimal improvements to site quality on the scale of 1 post, but global improvement to the average site quality, and in my opinion that can only be achieved by setting a proper standard for questions and answers.

robjohn

@user21820 So a good answer is grounds for keeping a questino?

user21820

@robjohn No. Only excellent answers on the level of the one I linked to, and the question must have intrinsic mathematical interest.

Bad question ∧ ( Uninteresting ∨ No excellent answer ) ⇒ Should be deleted.

robjohn

@user21820 "excellent" vs "good" is a judgement call.

user21820

Yes of course, and so is "interesting". Everything ultimately is a matter of opinion.

robjohn

May 30, 2019 15:23

depends on your interests, etc.

I think that this question is of intrinsic interest because it raises the question in my mind about the asymptotic expansion. The first term is simple, the further terms are difficult and I am very happy with my answer (whether it is "excellent" is a judgement call).

I could move my answer to the duplicate source on that one.

I had not seen the original before I answered

user21820

@robjohn That's exactly what I've always suggested; move answers worth keeping to good questions, and delete the bad questions. And of course, you can do that easily here since you're a moderator.

robjohn

@user21820 being a moderator doesn't help. I still need to copy the answer by copy/paste. I can delete the question in one vote, but I don't like to do that except in extreme cases.

user21820

May 30, 2019 15:39

@robjohn Oh I didn't know moderators can't move answers, but anyway it's still merely a copy-paste, and the question itself can be deleted by 3 users.

robjohn

However, the duplicate source is not really a better question.

just more answers.

The thing that got my interest was the asymptotic expansion.

and I am really happy with how that worked out.

user21820

@robjohn I agree that it's not a good question, but (in my opinion) it's better than the later one. As for interest in the asymptotic expansion, I'm not sure how it's relevant to this discussion. I also like asymptotic expansions, but my interests are a separate issue from site quality.

robjohn

"Interesting" was a quality you were looking for above ;)

When asking about limits, the next question is if there is an expansion, that is how it is relevant.

How does it approach the limit

user21820

I know that, but to me the question at hand has no intrinsic interest. There are tons of limits I can solve via asymptotic expansion, and only a small handful of them are intrinsically interesting.

robjohn

In that question, it was that getting the asymptotic expansion is not via one of the usual methods. A new method was needed.

That made it intrinsically interesting to me

I didn't see immediately how to get the expansion

And we seem to disagree on what is interesting in this case

user21820

May 30, 2019 15:52

@robjohn Not at all. It's a standard technique to cut it up into pieces and apply different bounds. It is obvious that the sum over k∈ω(1) is ο(2^n), so we just need to bound the sum over k<f(n) for some f such that f(n)∈ω(1) with f growing sufficiently slowly. That's easy.

robjohn

To get the limit is easy. I did that just looking at the question on the front page. The asymptotic expansion is not so easy.

user21820

So you're just supporting my point that the question is bad and you should simply have posted your question about the asymptotic behaviour of the sum with your answer, instead of answering the bad question.

It's your question after all, not that asker's.

There's a answer-my-own-question checkbox on the ask-question page, for precisely that purpose...

robjohn

certainly that goes way beyond answering that the limit is 0, but what good answers just stop at answering the question asked?

$Mathematics$ CURED

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