# Tag management 2019

New year, new tag management thread.

Rules of the game are basically the same:

• A particularly bad tag (a rule of thumb: «if I can't imagine a person classifying a tag as either interesting or ignored, I'm getting rid of it»),
• A tag that should be a synonym of an existing one,
• A tag that used for two or more completely unrelated things,
• A need to create a new tag;
• Wait a couple of days before implementing a suggestion.
• After the problem described in an answer is resolved, please edit it to say so.

Also, note that one may use [tag:calculus] for , i.e. tags on the main site, and [meta-tag:discussion] for , i.e. for tags on the meta site.

Proposal: create "derangements" tag

I have a sense that the search bar doesn't serve very well for finding combinatorics problems about derangements. It's especially hard to search for very basic problems involving them, like the hat-check problem. Another question that seems relatively common is solving and relating the two different canonical recurrence relations for the sequence.

I would contrast this with Catalan numbers, which currently has a tag attached to 297 posts. Honestly, I don't know if that's a large or a small number in terms of justifying a tag, but I would expect that derangement problems would be roughly as common.

Proposal: Hyphenate.

Reason: Hyphenation improves readability, and is standard practice.

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• There is only one question tagged crossedproducts. I am not sure that I see the utility of such a tag and, were it up to me, I would delete the tag rather than fix the hyphenation. However, if the tag is to persist, I agree that it should be hyphenated. – Xander Henderson Nov 17 at 1:12
• @XanderHenderson You're probably right. I'm still leaving this here, so it can be considered in the future. – URL Nov 17 at 2:34
• Absolutely! Thumbs up emoticon! – Xander Henderson Nov 17 at 2:59

Should we have a tag?

We have quite a few related questions that are currently spread across different nearby tags (such as , , and ) but no one tag to unite them.

• Here is a similar search restricted to questions, it gives 158 results at the moment. BTW I have asked Michael Greinecker about this tag proposal in chat, so far I got no response. – Martin Sleziak Aug 18 at 6:58

Proposal: create "visualisation" for

The tag synonym instructions suggest the following.

If you know of common, alternate spellings or phrasings for this tag, add them here so we can automatically correct them in the future. For example, suggest “bike” as a synonym for bicycle, or “sock” for socks.

In , we use "visualisation" instead of . French regular verbs end more commonly in "-ser" then in "-zer". Searching "visualization" on French.SE gives you nothing. Since French and English develop independently and interdependently, both spellings appear in the Anglo-Saxon world. Thus, "visualisation" can be qualified as an alternate spelling of .

• I don't think it's really worth creating French version of every tag... On the other hand, I think this spelling is sometimes used in British English, so it could be useful. – Arnaud D. Feb 16 at 23:05
• Once one has types 'visuali' the system will propose the tag. Not needed. Plus, what about opitimiz|sation, and all its variations. Parametriz|sation etc. – quid Feb 25 at 19:25

Proposal: create "geometry-without-trigonometry" tag

Similar to the limits-without-lhopital tag, we should have a geometry-without-trigonometry tag. Many times the OP posts a problem hoping to find an "elementary" solution but the answers use trigonometry. The OP may understand trigonometry but wants a pure geometrical solution or he may be in middle school and have no idea what is trigonometry.

The tag geometry-without-trigonometry will hopefully let us avoid such problems just like limits-without-lhopital did.

Proposal: Keep tag for questions related to formulas found specifically in the book Table of Integrals, Series, and Products.

There are currently about 120 questions about formulas found in the above book, so I have tagged some of these questions with .

Although some people have pointed out that this type of meta-tag is frowned upon, I still believe that it provides added value.