I suggested an edit to this post mainly to add links to the paper. I believe that this is considered a good thing to do: Is it worth editing old posts to add links for references?.

When editing the post I have noticed that it is only tagged semiring. So I wanted to add also top-level tag. I went for ra.rings-and-algebras. This one seemed (to me) the closest to semirings. If you think that this is not a good choice and you have an idea for a better top-level tag, please, do edit the post further.

This post is also missing top level tag, but I wasn't sure what would be a good choice:

BTW when editing that post I only removed the deprecated geometry tag. I was surprised a bit to see that also the beginning of the post "Dear all" has been removed.

I know that SE software removes salutations. But I would expect that it is removed already when the question is posted. The most likely explanation is salutation removal was only implemented after that question is posted (it is from 2011) or that the version of SE engine which was used until MO joined SE network did not have this feature.

And since I already mentioned geometry tag. The tag-info explicitly says: "Deprecated; please do NOT use this tag, use a more specific tag." But I was not able to find on meta or on tea discussion where this was actually decided. Does anybody have link to that discussion?