Tagging - 2016-10-20

12:32 PM

The first "naturally tagged" question has been asked. And exactly the thing I dislike about new tags happened. It was tagged with relations and well-orders. Sure, there are some 43 people following the former tag, so it is likely one of them would have come across the question, but the tag itself doesn't really fit the question. I only saw it by chance (and omnipresence, I guess). And this is my main gripe against new tags: since a lot of users, especially new, don't know how to tag a question properly, introducing new tags introduces confusion and limits proper exposure. — Asaf Karagila 4 mins ago

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Q: Well ordering theorem, partial ordering

At the Wikipedia page for the well ordering theorem For every set X, there exists a well-ordering with domain X. Furthermore, a well ordering is defined to be a strict total order so that each subset has a least element. Now I have a couple of questions about this: Does this mean that the s...

To be honest I do not know what @Asaf's mean by saying that the tag itself doesn't really fit the question. That question is definitely about well-orderings (and well-ordering principle).

I wonder whether Asaf will receive my ping, thanks to omnipresence.

Asaf Karagila

2:37 PM

@MartinSleziak I meant the relations tag, obviously the well-orders fits there just fine.

Martin Sleziak

2:47 PM

Wow, you really are omnipresent.

@AsafKaragila I still fail to see how existence of (well-orders) is at fault for incorrect tagging. (I'd say the situation where at least one tag is correct is better.)

I can't help it, but I still think that this tag could be useful. (But I think I said so a few times before.)

Asaf Karagila

@MartinSleziak Well. Maybe. But it's not unthinkable, and it won't be a first either, that someone tags a question just with that "correct tag".

Martin Sleziak

And that would be, in my opinion, perfectly ok.

Asaf Karagila

I guess I just don't like fragmentation.

Martin Sleziak

You cannot expect a tag who has been around for a few days, to have followers.

Probably I should have not said perfectly ok.

But if this helps the OP to find at least one relevant tag, that's a good think.

I certainly agree that if some question about well-orders also belongs to large area (such as order-theory or set-theory), then that tag should be added as well.

Asaf Karagila

Sure, it's better than those people who tag set theory questions as analysis, or, you know, geometric group theory. But I guess I just don't know yet if this tag is truly useful as a "spice tag", something that doesn't go alone very well.

Martin Sleziak

3:00 PM

@AsafKaragila One of the possibilities suggested in that thread is synonym between well-orders and ordinals. (In some direction.) That would not cause any additional fragmentation - we would just add a synonym to already existing tag.

Asaf Karagila

@MartinSleziak Yes, that is correct, but not every question about well-orders is a question about ordinals.

If anything, then order-theory is a better master here.

Martin Sleziak

@AsafKaragila Of course, I know that. But we have many tag synonyms where the two things are not exactly the same, we have just decided to tag them using the same tag. And well-orders and ordinals are definitely very close to each other.

Asaf Karagila

But I guess we can re-evaluate this in six months.

Martin Sleziak

I do not like (order-theory) as a synonym.

Asaf Karagila

How come?

Martin Sleziak

3:04 PM

For example algebraic-closure is not the same thing field-theory, yet we have synonym.

I do not like (order-theory) as a synonym, because it is too general. We would lose all information that (well-orders) tag adds. (I guess this is what "How come?" referred to.)

Asaf Karagila

@MartinSleziak Yes, but well-orders which are not already ordinals, are an object dealt with within order theory. Much like how algebraic closures are---on a basic level---dealt with in field theory.

Martin Sleziak

@AsafKaragila That sounds like a plan. So you would be open to let the tag "live" for some time and then check how it looks like.

Asaf Karagila

@MartinSleziak Yes. I'm nothing if not flexible.

I mean, I can touch my right ear with my left hand from behind my back. Not many people can do that.

Martin Sleziak

I'd say that I do not like (well-orders) $\to$ (order-theory) for the same reason I would not like to see the synonym (lattice-orders) $\to$ (order-theory).

Asaf Karagila

Now. I really reached the point where procrastination is not an option. I bid you adieu and good luck.

Martin Sleziak

3:10 PM

Yes, it can proabaly be considered subtag, but that is not reason enough to make it a synonym.

See you later! Have a nice day!

Martin Sleziak

4:11 PM

What do you think about the synonym binomial-theorem $\to$ binomial-coefficients which was recently suggest (it's another one by JonMark Perry.)

My opinion on that tag synonym is: Definitely not without a previous discussion on meta.

And perhaps somebody with knowledge of that area could comment on kalman-filter $\to$ bayesian-network, which was also suggested. (Personally I do not like it that much. Probably the idea of one common tags for this type of filters seems better.)

Martin Sleziak

5:56 PM

BTW if somebody wondered about this comment:

3 hours ago, by Asaf Karagila

Sure, it's better than those people who tag set theory questions as analysis, or, you know, geometric group theory. But I guess I just don't know yet if this tag is truly useful as a "spice tag", something that doesn't go alone very well.

It was kind of an inside joke related to tags used originally here.

Did you roll a die to decide the tags for this question? — Asaf Karagila Oct 12 at 11:44

What does this have to do with geometric group theory? (your tags) — Paul Plummer Oct 12 at 13:43

it is used in the theory of asymptotic cones, which was the key ingredient in proof of Gromov's theorem on groups of polynomial growth — Sunny Rathore Oct 12 at 13:46

I feel like that is stretching what tags are used for, given that it doesn't seem like there is any geometric group theory in this question. (a lot more questions would be tagged ggt if some idea, tool, or technique, in the question, was used at some point in the area). — Paul Plummer Oct 12 at 13:55

I just added because people from ggt background know these things and they can quickly answer my question — Sunny Rathore Oct 12 at 14:04

Surely people from geometric group theory can answer basic questions about intersection and union of sets. Should we start tagging all discrete mathematics questions with these tags also? — Asaf Karagila Oct 13 at 8:27

Transcript for

$Mathematics$ Tagging