Revisiting the “partitions” tag

Almost six years ago, Michael Hardy raised the issue of the "partitions" tag being used for some very different concepts, and subsequently edited its tag wiki excerpt to at least be clear about what the various concepts covered were.

Two months ago the tag wiki was changed to be solely about integer partitions.

However, the new questions in the tag since then continue to be a mixture of questions about integer and set partitions.

Has the time come for a retagging effort to separate unambiguous tags for and , and if so should it be done completely manually (a long project for a 1000-question tag) or by mod superpowers with manual fix-ups for questions which end up badly tagged?

• I think it would make sense to address this issue. I do not have a fixed plan to propose, though. However, it is not very clear to me what you mean with "by mod superpowers with manual fix-ups for questions which end up badly tagged"? Do you mean to delete or to rename the tag or something else? – quid Oct 13 '17 at 23:34
• @quid, I mean renaming the tag (which I believe mods can do) and then manually retagging questions which end up in the wrong tag (which anyone with a bit of rep can do). – Peter Taylor Oct 14 '17 at 6:20
• Thank you for the clarification. Yes, moderators can essentially rename tags (technically they can't rename it but they could merge it into another tag with a different name, which is about the same) – quid Oct 14 '17 at 11:31
• Some details of what mods can/cannot do are explained here: Can you change the name of a tag? (But I think quid's comment sums it up quite sufficiently.) – Martin Sleziak Oct 14 '17 at 12:31
• Would the partitions tag be appropriate for this question: math.stackexchange.com/questions/2475870/… ? – Mr. Brooks Oct 18 '17 at 21:36
• Follow-up – Peter Taylor Jun 27 '18 at 13:37

I looked through the tag a bit. Michael Hardy identified a further use-case in addition to the two mentioned in the question, namely partitions of intervals in the context of integration, which does not really fall under set partitions.

Further there is something called the partition problem for which the tag also gets used sometimes. I am not sure we need an actual tag for that but that's somewhat of a separate concern.

I propose:

1. Keep the current one for partitions of integers, which is the most common usecase I think. (I would not yet rename the tag, but likely at the end.)

2. Retag what does not fit to (as appropriate):

3. If some other use-case bubbles up in the process mention it here so we can decide if we add a further tag or if maybe the tag can be dropped there.

If somebody has better ideas for the names, please, speak up.

Update: the tag was already created.

Modified proposal:

2.' Retag what does not fit under partitions of integers to (as appropriate):

And drop the tag altogether where none of the three fit.

Update 2: I went ahead and created the tag for integration related questions.

• There is a construction in topology called "partitions of unity", possibly too specialized to have its own tag. – hardmath Oct 15 '17 at 0:38
• Good point! I know the notion but did not think of it. Since it is a rather standard name it could make sense to have it as a tag. A quick search in the partitions tag brought up a handful of questions only; but over the full site there might be a decent number. – quid Oct 15 '17 at 0:49
• What about plane partitions? There seems to be about 4 plane partition questions with the (partitions) tag and possibly a handful more without it. – Trevor Gunn Oct 15 '17 at 2:41
• The partition problem can be phrased in the language of set partitions, so I don't think it would be wrong to use that tag on those questions. I do think it would be wrong to create a tag for them: it's just a special case of the subset sum problem, which doesn't have its own tag (or any consistency in tagging). It may be worth creating a subset-sum-problem tag, but even that seems generous compared to other more famous problems without one. Maybe algorithms linear-programming? – Peter Taylor Oct 15 '17 at 5:58
• There are also graph partitions. But I am not sure whether there were many questions about them. – Martin Sleziak Oct 15 '17 at 6:20
• @TrevorGunn I'd leave "plane partitions" under integer partitions, while for partitions of the plane and other such things tesselations or tiling should work. – quid Oct 15 '17 at 11:52
• @PeterTaylor I agree a separate tag might not be needed, but for the process of retagging it could be simplest to have it. The flavor of questions on "set partitions" is, I feel, a bit different. Thus I am not convinced this tag would be a good fit. I'd just drop it altogether instead and tag something along the lines you mentioned. In the same vein, I am not sure that it will ultimately be worth it to keep the partitions for integration as a tag. But that's easier to decide once it is separated from the rest. – quid Oct 15 '17 at 11:59
• I actually just posted a question that probably deserves the set-partitions tag, so I created it. – David Z Oct 16 '17 at 4:23
• @DavidZ good idea. But in fact you used the singular so your link does not work. (I think plural is more standard on this site so you might want to change it. But it's not a big deal.) – quid Oct 16 '17 at 11:54
• Oh, whoops. Well, it actually won't let me make such a minor change in the tags. Hopefully someone else can change it, or there will be a synonym created. – David Z Oct 16 '17 at 16:44
• @DavidZ I'd say never mind then. (I forgot about that system's restriction.) It is not the first tag that deviates from the plural (and if it were up to me it would be that singular would be default anyway, but that ship sailed years ago). – quid Oct 16 '17 at 17:05
• @DavidZ, surely the name can be fixed by removing the tag completely, and then adding it again? At worst you would need to wait $24+\epsilon$ hours in between for the unused singular tag to be autodeleted. – Peter Taylor Oct 23 '17 at 13:53
• @PeterTaylor I could do that, but quid did say it's probably not worth the trouble, and in any case it's easy enough for any of the mods to change the tag if they like. (I myself have no particular preference between singular and plural.) – David Z Oct 23 '17 at 18:01
• Re "I would not yet rename the tag, but likely at the end": I think it would be useful to rename it to integer-partitions now. It's been six months since we separated the tags, but I'm still seeing a lot of necessary retaggings. I personally have moved more questions from partitions to set-partition in April than there have been genuine integer partitions questions. – Peter Taylor Apr 16 '18 at 14:09