Question: New year, new tag management thread.

Rules of the game are basically [the same](https://math.meta.stackexchange.com/q/27653/43351):

* Post your suggestion as an answer here if you see
	+ 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;
* Upvote/downvote/comment as your agree/disagree with suggestions, so please post different suggestions in separate answers;
* Wait a couple of days before implementing a suggestion.
* After the problem described in an answer is resolved, please edit it to say so.
* If your tag suggestion exists in a separate question, please provide a link to the question in your suggestion.

See also:

* The [list with pending and approved synonyms](https://math.stackexchange.com/tags/synonyms).
* The [tagging chatroom](http://chat.stackexchange.com/rooms/3740/tagging) for extended discussion on tagging.
* [Last year's thread](https://math.meta.stackexchange.com/q/27653/43351) to look for suggestions that need to be implemented.

Also, note that one may use `[tag:calculus]` for [calculus](https://math.stackexchange.com/questions/tagged/calculus "show questions tagged 'calculus'"), i.e. tags on the main site, and `[meta-tag:discussion]` for [discussion](/questions/tagged/discussion "show questions tagged 'discussion'"), i.e. for tags on the meta site.

Answer: 
> 
> **Resolved.** [generalizedeigenvector](https://math.stackexchange.com/questions/tagged/generalizedeigenvector "show questions tagged 'generalizedeigenvector'") has been renamed [generalized-eigenvector](https://math.stackexchange.com/questions/tagged/generalized-eigenvector "show questions tagged 'generalized-eigenvector'").
> 
> 
> 

**Proposal: rename "generalizedeigenvector" to "generalized-eigenvector"**

Pledge originally initiated by WillG in [this suggested tag wiki excerpt edit](https://math.stackexchange.com/review/suggested-edits/1147115). I support this proposal since it's a common pratice to separate words with hyphens in tag names in order to increase readability, like [ode](https://math.stackexchange.com/questions/tagged/ode "show questions tagged 'ode'"), [real-analysis](https://math.stackexchange.com/questions/tagged/real-analysis "show questions tagged 'real-analysis'"), [generating-functions](https://math.stackexchange.com/questions/tagged/generating-functions "show questions tagged 'generating-functions'"), etc.
**Resolved (mostly)** Creation of a tag [gcd-and-lcm](https://math.stackexchange.com/questions/tagged/gcd-and-lcm "show questions tagged 'gcd-and-lcm'"). Merge of the GCD part, not yet merged the LCM part, in case some objection emerges. The tag wiki might need some (more) attention. 

---

Proposal: merge [gcd](https://math.stackexchange.com/questions/tagged/gcd "show questions tagged 'gcd'") and [lcm](https://math.stackexchange.com/questions/tagged/lcm "show questions tagged 'lcm'")

We tend to combine homologus objects into one tag, like [supremum-and-infimum](https://math.stackexchange.com/questions/tagged/supremum-and-infimum "show questions tagged 'supremum-and-infimum'"), [limsup-and-liminf](https://math.stackexchange.com/questions/tagged/limsup-and-liminf "show questions tagged 'limsup-and-liminf'") and [even-and-odd-functions](https://math.stackexchange.com/questions/tagged/even-and-odd-functions "show questions tagged 'even-and-odd-functions'"). It's well known that $ab = \gcd(a,b) \times \mathrm{lcm}(a,b)$, so knowing the [gcd](https://math.stackexchange.com/questions/tagged/gcd "show questions tagged 'gcd'") implies the same for [lcm](https://math.stackexchange.com/questions/tagged/lcm "show questions tagged 'lcm'"), and *vice versa*.

The [majority](https://math.stackexchange.com/search?q=%5Bgcd%5D+AND+%5Blcm%5D) of [lcm](https://math.stackexchange.com/questions/tagged/lcm "show questions tagged 'lcm'") questions are also tagged with [gcd](https://math.stackexchange.com/questions/tagged/gcd "show questions tagged 'gcd'").