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**: [mirror-symmetry](https://math.stackexchange.com/questions/tagged/mirror-symmetry "show questions tagged 'mirror-symmetry'") is now created.
> 
> 
> 

**Proposal: Create "mirror symmetry" tag**

[mirror symmetry](https://mathoverflow.net/questions/tagged/mirror-symmetry) is already a tag in MO, and there're already several questions about it now in MSE: [(1)](https://math.stackexchange.com/questions/315712/mathematics-and-physics-prerequisites-for-mirror-symmetry), [(2)](https://math.stackexchange.com/questions/773527/construction-of-virtual-class-at-homological-mirror-symmetry), [(3)](https://math.stackexchange.com/questions/2149233/mirror-symmetry-of-calabi-yau-surfaces), [(4)](https://math.stackexchange.com/questions/1750814/mirror-symmetry-of-elliptic-curve), [(5)](https://math.stackexchange.com/questions/6484/about-homological-mirror-symmetry).

Here is an [introductory](https://www.dpmms.cam.ac.uk/~mg475/current.pdf) to mirror symmetry mathematically which says mirror symmetry introduces a correspondence between complex geometry and symplectic geometry, so actually it doesn't require strong physical background in string theory (physically).

---

I've already created [mirror-symmetry](https://math.stackexchange.com/questions/tagged/mirror-symmetry "show questions tagged 'mirror-symmetry'") and begin to add this tag to relevant questions gradually, and welcome to improve tag info and usage :)
**Proposal: pluralise [alternative-proof](https://math.stackexchange.com/questions/tagged/alternative-proof "show questions tagged 'alternative-proof'")**.

Reasons:

1. It's a convention to have pluralised tag names if possible.
2. A proposition sometimes has multiple proofs.