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.** [cauchy-riemann-equation](https://math.stackexchange.com/questions/tagged/cauchy-riemann-equation "show questions tagged 'cauchy-riemann-equation'") is now [cauchy-riemann-equations](https://math.stackexchange.com/questions/tagged/cauchy-riemann-equations "show questions tagged 'cauchy-riemann-equations'").
> 
> 
> 

**Proposal: pluralize [cauchy-riemann-equation](https://math.stackexchange.com/questions/tagged/cauchy-riemann-equation "show questions tagged 'cauchy-riemann-equation'")**

Because… well, you know: there are two of them.
> 
> **Resolved.** [semisimple-lie-algebras](https://math.stackexchange.com/questions/tagged/semisimple-lie-algebras "show questions tagged 'semisimple-lie-algebras'") is created.
> 
> 
> 

**Proposal: Create "semisimple-lie-algebras" tag**

[Semisimple lie algebras](https://en.wikipedia.org/wiki/Semisimple_Lie_algebra) is an important class of Lie algebras, and we already have tag [semi-simple-rings](https://math.stackexchange.com/questions/tagged/semi-simple-rings "show questions tagged 'semi-simple-rings'").