The tag elegant-proof has been created, but then the OP deleted the question where they created the tag: What is the most elegant proof that the sum of formal power series $\sum_{i\geq 1} F_i(x)$ converges iff $\lim \deg F_i(x) = \infty$?

Over at MO they have a tag called slick-proof. Different site, different tags.

I see that Michael Albanese created spin-geometry tag.

@MichaelAlbanese It might be reasonable to create also tag-wiki for this tag - as Daniel Fischer suggested in his comment.

Maybe it can be formulated in a way which makes clear that questions about spinors belong under this tag.

The tag spin-geometry has been removed from that question - I have added it back. (But I certainly do not plan to get into edit war - if the tag is removed again, I'll let it be or perhaps ping the editor.)

Probably I should add link to the conversation in Mods' Office related to the tags spinor and spin-geometry: chat.stackexchange.com/transcript/20352/2017/5/13 and chat.stackexchange.com/transcript/20352/2017/5/11