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I recently found some mistake in the calculation in an answer.

The formula $\color{red} {\int_{x=0}^\infty e^{-(ax^2+bx)}\,dx=\frac{1}{2}\sqrt{\frac{\pi}{a}}\exp\left(\frac{b^2}{4a}\right)}$ used in the answer is wrong, and caused confusion, as can be seen in the comments.

However, the answer can be fixed by changing the limits from $-\infty$ to $\infty$ in some intermediate steps, and using ${\int_{x=-\infty}^\infty e^{-(ax^2+bx)}\,dx=\sqrt{\frac{\pi}{a}}\exp\left(\frac{b^2}{4a}\right)}$.

I suggested an edit to correct it, but it was rejected on the following ground.

The edit does not improve the quality of the post. Changes to the content are unnecessary or make the post more confusing.

As mentioned in the comments, the previous version of the answer did cause some confusion, which I addressed in the suggested edit.

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    $\begingroup$ Looks like I called it wrong on that edit, for which I sincerely apologise (I'm relatively new to reviewing) The wording of the rejection reason is not my own (we can only tick a box). The reason for my rejection was that I was under the impression edits were primarily to fix formatting, spelling and grammar issues, rather than mathematical mistakes (I had some of my own suggested edits rejected by very experienced users seemingly for this reason, so figured it was not the done thing). I'm still learning how all this works and will bear in mind what you have said :) $\endgroup$
    – user829347
    Feb 10, 2022 at 18:27
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    $\begingroup$ When you are merely suggesting edits, you need to understand that suggested edits are not intended to change content. Rather, a comment pointing out the error to the poster is the best policy. $\endgroup$
    – amWhy
    Feb 10, 2022 at 18:49
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    $\begingroup$ How to make or suggest good edits. $\endgroup$
    – amWhy
    Feb 10, 2022 at 18:54
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    $\begingroup$ @Oliver, you actually followed site guidelines in your vote. $\endgroup$
    – amWhy
    Feb 10, 2022 at 18:55
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    $\begingroup$ Related discussion I appreciate your need to edit, but I am of the belief that this answer is more wrong than a mere typo : it's the correction of an entire substitution, and the fix suggested regarding the lower limits doesn't sound obvious enough to me, at least. Site rules would recommend a rejection. If writing a new answer is out, consider adding stronger comments on corrections. $\endgroup$ Feb 10, 2022 at 22:41
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    $\begingroup$ By stronger, I think the assertions made so far in the comments ue phrases/words like "shouldn't it be?" , "can" etc. I would suggest that you add comments to the effect : the formula $...$ is wrong, but correcting the lower limit to $-\infty$ (which can be done because even function etc.) and proceeding with the calculations gives the right answer. This may be the best thing to do in this situation. $\endgroup$ Feb 10, 2022 at 22:44
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    $\begingroup$ One thing I have noticed when trying to tidy up very poorly articulated questions is that sometimes the OP might not understand that the edit is simply a better way of expressing the same thing. Even if the post is 'better' or 'corrected', if the OP doesn't understand their own question anymore, that is surely a problem $\endgroup$
    – user829347
    Feb 10, 2022 at 22:46
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    $\begingroup$ @SarveshRavichandranIyer The answer was more or less correct. Maybe OP did not notice the issue with the lower limit (sometimes it happens that we do some calculation in our head, and while writing it down, we make some mistakes in the intermediate steps without thinking much). There was a mistake in the intermediate steps in an otherwise good answer and I wanted to fix it. I don't get why there is so much backlash to correct a wrong calculation. $\endgroup$ Feb 11, 2022 at 2:43
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    $\begingroup$ @ArchismanPanigrahi I understand : this situation may seem a bit blown out of proportion, but to me it doesn't strike, immediately, that the fix made is simple. The way I'm thinking of this is that one doesn't need to go to the even version of the integral if one doesn't actually try to make the $b/2a$ substitution and see that it fails because the lower limit isn't $0$. The change of the limit is insight that may have been beyond what the original OP is thinking of. Having said that , the user has been inactive , so it is very much a gray area. $\endgroup$ Feb 11, 2022 at 4:03
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    $\begingroup$ I mean, the edit is correct, and "substantial" enough, and makes no stylistic changes, so it ticks many boxes according to me. The contention is likely over how much the edit may infringe upon the original OP's thoughts and writing, and how much the original OP's thoughts matter(especially here when they haven't been inactive in some time). If there is a difference of opinion over these things and over what site rules may say, then you are seeing it reflected in the comments. I don't think it's a backlash, it has been very quiet compared to some threads in recent times! $\endgroup$ Feb 11, 2022 at 4:20
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    $\begingroup$ @amWhy, where exactly does it say on that meta question that suggested edits, or edits in general shouldn't change the content? It says that "Edits should typically be used to make significant, important improvements to a post. When you make an edit, please ensure that the changes you are making actually make the post noticeably better." and doubles down on that for suggested edits. If the equation in the post was wrong, then isn't fixing it a "significant, important improvement"? $\endgroup$
    – ilkkachu
    Feb 11, 2022 at 8:20
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    $\begingroup$ @ArchismanPanigrahi There is no backlash, getting a suggested edit rejected is completely normal. I had 20 of my edits rejected, some of which I completely disagreed with. I think you are able to resubmit the edit if you so wish :) $\endgroup$
    – user829347
    Feb 11, 2022 at 16:58

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Your edit was perfectly fine and should have been accepted. Sometimes reviewers simply make mistakes, especially when understanding the reason for the edit involves some nontrivial mathematics. You can decrease the chance of this happening by including more details in your edit summary to explain the correction you are making.

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    $\begingroup$ Isn't there a point at which the explanation needed becomes too nontrivial to treat the edit as correcting a typo? The dictum on the Welcome page is "Use edits to fix mistakes, improve formatting, or clarify the meaning of a post." $\endgroup$
    – hardmath
    Feb 10, 2022 at 16:58
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    $\begingroup$ There is but I don't think this edit is particularly close to that point. I also would disagree that correction edits are limited to "typos". More complicated corrections of minor mathematical mistakes that do not change the main ideas of the answer are also fine, especially (as in this case) when the errors were first pointed out years ago and the OP has not been around for years. $\endgroup$ Feb 10, 2022 at 17:12
  • $\begingroup$ Should I suggest the same edit once again, then? $\endgroup$ Feb 10, 2022 at 18:37
  • $\begingroup$ There's a reason, @Eric, that users under 2000 rep must have their edits evaluated, and the site policy is not to correct errors in posts: question or answers, but rather comment to the author of the post, describing the problem. $\endgroup$
    – amWhy
    Feb 10, 2022 at 18:51
  • $\begingroup$ How to make or suggest good edits. $\endgroup$
    – amWhy
    Feb 10, 2022 at 18:54
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    $\begingroup$ @amWhy Leave a comment even if the OP has not been online for years? $\endgroup$
    – user829347
    Feb 10, 2022 at 18:54
  • $\begingroup$ Well, there is plenty a suggested editor can improve, without delving into posts from way back when, @Oliver, one of the close voters of this post? $\endgroup$
    – amWhy
    Feb 10, 2022 at 22:14
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    $\begingroup$ @amWhy I don't follow. I was one of the people who rejected the OP's suggested edit, if that is what you mean? (see my comment on the above question) $\endgroup$
    – user829347
    Feb 10, 2022 at 22:41
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    $\begingroup$ @amWhy If you're asking if I voted to close this post, then I did not. I quite appreciate that the OP raised this question $\endgroup$
    – user829347
    Feb 11, 2022 at 16:45
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    $\begingroup$ @ArchismanPanigrahi I have had a few of my suggested edits that were correcting mathematical mistakes rejected by people who did not understand the particular mathematics involved. Like Eric Wofsey suggests, I would then resubmit the edit with a more detailed explanation in the summary, hoping that a better batch of people would review the edit, and it would usually be accepted. $\endgroup$
    – PatrickR
    Feb 12, 2022 at 6:04
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    $\begingroup$ @OliverHouse Not that it matters, but in an example for my particular case, the question involved concerned a rather specialized topic in topology. The rejecter's own questions and answers were mostly at calculus level, and presumably he judged the edit without taking the time to fully understand the notions involved. Anyway, no worry as a resubmit was correctly accepted by another batch of editors. $\endgroup$
    – PatrickR
    Feb 14, 2022 at 0:36
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I think your edit has merit. In general we should defer to the original poster on substantive edits, and the proposed change is substantive.

On the other hand the original poster has not been on Math.SE for several years. Trying to contact them other than through comments such as you left would be unjustified and possibly unwelcome.

In most such cases, I recommend leaving your comments in place, and then after a passage of a few days (the answer has been that way for years), posting your own answer with reference to the earlier one. Then you could also leave a new comment on the old answer alerting readers to your new one.

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    $\begingroup$ In this case it seems to be a simple computational error, I doubt if writing a new answer had any merit. (the QA there is not about this particular calculation anyway) $\endgroup$ Feb 10, 2022 at 16:13
  • $\begingroup$ @ArticChar Looking at the Comments left by Archisman on Tunk-Fey's Answer we can see more substantive criticism than what I consider a simple computational error. If there were a way to treat the correction as "typographic", it would be allowable. $\endgroup$
    – hardmath
    Feb 10, 2022 at 16:35
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    $\begingroup$ @amWhy: The situation is that one Comment was left in 2018, about the idea of integrating from $-\infty$ to $\infty$ (instead of zero to $\infty$), while another one was left yesterday about a constant multiplier. So the timeliness as well as typoness are a little vexed. The ideas for improvements are genuine. $\endgroup$
    – hardmath
    Feb 10, 2022 at 19:36

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