I would like to get some reactions to the idea of merging several tags under an umbrella "infinitesimal". The motivation is that the individual tags each have few questions, and the existence of separate tags makes it more difficult for a user to become aware of other related questions. The tags involved are infinitesimals, nonstandard-analysis, surreal-numbers, and surreal-analysis. Any comments?
Note 1. Following suggestion by @quid, I propose "to make it the master tag in tag synonym pairs without merging. Then all current tagging would stay as is, and only all future instances of the minor tag would be auto-re-tagged to the master." Actually I don't fully understand the technicalities of this proposal but I think it would be better than deleting the tag.
Note 2. The tag "non-archimedean fields" actually includes two distinct topics itself, namely ordered nonarchimedean fields such as Levi-Civita fields, on the one hand, and ultrametrics (e.g. p-adics), on the other.