A MO user (Myshkin) has just edited the title of a question of mine (here) to make it shorter. The old title was:

Ref request: If the natural density (relative to the primes) exists, then the Dirichlet density also exists, and the two are equal

whereas the new title is:

If the natural density exists, then the Dirichlet density also exists, and the two are equal

I must confess that I find this annoying:

1) There is an upper bound to the length of a title, which is imposed by the software. So, it seems to me that any other consideration about the length of a title is arbitrary and shouldn't be used as a justification for editing a post insofar as a title provides sensible information that would be lost by making it shorter.

2) The new title by Myshkin is certainly shorter than the old one. Yet, it's also less precise and more confusing, and I'm not convinced that shortness is more valuable than clarity. In my limited experience, algebraic number theorists assume the terms "natural density" and "Dirichlet density" refer, by default, to the quantities that I'm considering in my question, and that's probably why Myshkin has thought the old title contained some redundancy. However, that's not the case with analytic or combinatorial number theory, which is the origin of much confusion and the explanation for the parenthesis "(relative to the primes)" I had put in the old title.

So I'm writing here to ask if there is a policy on MO to deal with this kind of "issues". To be more explicit, I think I'd like to roll back to the old title, or better to the following shorter version of the old title:

If the natural density (relative to the primes) exists, then the Dirichlet density also exists, and the two are equal

But it seems unfair to me to do it without asking for the advice of the community.

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    $\begingroup$ For general advice on question titles, please see: Titles should be stand-alone summaries of questions without depending on tags. $\endgroup$ Commented Feb 8, 2016 at 21:22
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    $\begingroup$ "Policy on MO" is the net effect of decisions by hundreds of independent users. Personally, I would have used the title, "Natural density and Dirichlet density." $\endgroup$ Commented Feb 8, 2016 at 23:38
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    $\begingroup$ @GerryMyerson Dirichlet density vs natural density. Then we can still have "Dirichlet density and natural density" and "Natural density vs Dirichlet density." Frankly, this is the type of titling that leads to "Compute the integral 7" on Mathematics $\endgroup$
    – user9072
    Commented Feb 9, 2016 at 8:09
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    $\begingroup$ @quid, the main purpose of a title is to let people know whether they're likely to be interested in reading the question. The people who would read a question with the title, "Ref request: If the natural density (relative to the primes) exists, then the Dirichlet density also exists, and the two are equal" are, I reckon, pretty much the same people who would read a question with the title, "Natural density and Dirichlet density." Another purpose of the title is to facilitate searches, and anyone searching for natural/Dirichlet density will find it with either title. $\endgroup$ Commented Feb 9, 2016 at 11:56
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    $\begingroup$ @GerryMyerson. Haven't you just described one of the main purposes of a title? I don't see any reason why it should be the main one. I'm probably biased in my judgment, but I've always believed that a title, as long as space is available, should provide as much information as possible about the actual content of whatever the title is meant for. How could you make a difference between distinct threads both of which are concerned with properties of the Dirichlet and natural densities? Right, you couldn't. On the other hand, using "Ref. request" was a bad idea, that's definitely clear. $\endgroup$ Commented Feb 9, 2016 at 13:28

1 Answer 1


The guidelines in How do I write a good MathOverflow question? have a section on titles, which says:

Use your title to convey as much information about your question as possible. Since the tags already convey the general subject area of your question, the title should communicate the question itself as faithfully as possible. If necessary, leave out hypotheses in the title, and in the body of the question, explain why the question requires those hypotheses.

Don't be afraid to make your question title long. Titles are allowed to be anywhere from 15 to 250 characters long. 140 characters (the length of a tweet) takes up about two full lines on the home page, so try to keep it less than that. But 140 characters is a lot longer than you might think. Too many people restrict themselves to 20 character titles. They're trying not to waste your time by making you read a long title, but they end up wasting more of your time because you have to actually open the question to see if it's interesting to you.

I would summarize this as informative titles are strongly encouraged; but do not over do it. (Note: it seems the 250 characters is not [anymore?] true; the limit is 150.)

There is also a post on Editing etiquette in general, which I would paraphrase very roughly as saying editing is fine and encouraged, and everybody should try to see the glass as half full rather than half empty.

How does this relate to the specific situation?

I think your original title was a good one with the possible exception of the "Ref. request:" at the start. I feel this is either not needed, as redundant with the tag or not precise enough (what I mean is you are not just after any reference but rather after the original source or something close to it, but you do not communicate this).

Also note that the first tag makes part of the title if the question page; thus with such a title you may end up with: "reference-request-Ref.-request:" as the start of the title of the page. (Your most common tag was nt.number-theory so this does not directly apply, but would you have asked about a result in ac.commutative-algebra instead it would.)

The parenthetical that got removed: my fist impulse would be that this is maybe too verbose for a title, but on second thought it happens not rarely (in any case it happened to me and I believe I observed it sometimes) that users are set on a track by what they see first (in the title) and then answer based on this even if the body explicitly over-rides it. In that sense, I think you have a point that it is of value to have it there.

tl;dr Your title was fine, with the possible exception of the quasi-tag "Ref. request:" and I can understand the editor, too. The final title, in the middle of the original and the original edit, is in my opinion the best of all, and the process worked.

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    $\begingroup$ When was the limit 250 characters? $\endgroup$
    – Asaf Karagila Mod
    Commented Feb 9, 2016 at 11:55
  • $\begingroup$ I wouldn't know. But then the text I quote is I believe from before I was around. $\endgroup$
    – user9072
    Commented Feb 9, 2016 at 12:32
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    $\begingroup$ I see... thanks. May I also suggest that if you want to go back to not being a round, similar to apparently three years ago, diet and exercise is a good idea! :-P $\endgroup$
    – Asaf Karagila Mod
    Commented Feb 9, 2016 at 12:44
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    $\begingroup$ The text was not written three years ago. It was already on MO 1.0, and I think from very early on. It just got copied over then. Thanks for the advice. I might create an account on Physical Fitness and see if it helps/ $\endgroup$
    – user9072
    Commented Feb 9, 2016 at 18:15
  • $\begingroup$ Yes, I guessed this was something taken from MO 1.0, as the SE 2 software should be more or less uniform all across the board, even here. At least in this aspect. Anyway whether or not you want to be a round is your call. :-) $\endgroup$
    – Asaf Karagila Mod
    Commented Feb 9, 2016 at 18:29
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    $\begingroup$ \O\ \O/ /O/ \O/ \O\ \O/ /O/ \O/ \O\ \O/ /O/ \O/ \O\ \O/ /O/ \O/ \O\ \O/ /O/ That's enough exercise for today. $\endgroup$
    – user9072
    Commented Feb 9, 2016 at 18:55
  • $\begingroup$ To finally answer your question: before May 9th, 2010. $\endgroup$
    – user9072
    Commented Feb 9, 2016 at 19:20
  • $\begingroup$ Many tags (eg math.lo) are useful for categorisation, but don’t add anything that can’t be inferred the rest of the title. But “Ref. request” and a few others add something which often can’t be inferred from the rest of the question title. On scanning the front page, the question titles are much more prominent than the tags, so I would guess I’m not the only person who’s grateful for the use of such quasi-tags, on the basis that question titles should summarise the question as self-containedly as possible. $\endgroup$ Commented Feb 14, 2016 at 0:46
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    $\begingroup$ @PeterLeFanuLumsdaine my point was that there are plenty of different types of reference request, and if one already writes this in the title one should be more specific than just reference request. Would it say "Where was it first proved [...]" or "What is the original source of [...]" than I'd be fine with it. And generally it is also a stylistic thing, I think it is better to integrate the information organically in the title rather than to tuck it on in a tag-like way. $\endgroup$
    – user9072
    Commented Feb 14, 2016 at 0:55

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