@psie Well, that would mean that you need to show that IF $\lim_{x\to a} f(x) = f(x)$, THEN you can always find an appropriate $V$ for any $U$, and vice versa.
heyho. any ideas how to call a monoid whose underlying "set" is a class or collection? I know that "large monoid" is used, but I want something that includes the type of size. so something like "monoid class" or "monoid collection", but that doesn't sound right to me.
for partial orders there is a very good choice: "partially ordered collection"
(a typical example of a large monoid is the collection of all sets with * = union of sets, 1 = empty set).
still I fail to see why small/medium/large doesn't serve you here: it does denote the type of size, under the usual convention that small sets are sets that live in whatever base Grothendieck universe you fix and every escalation in adjective moves you up one universe. If you want something more technical you could talk about $\mathfrak{U}_n$-monoids, I guess?
ad "small set," yes. ad "large set," I guess it depends on the audience. If I heard the words "large set," I would think you mean a set that lives at least one Grothendieck universe higher
the only thing I know is that I'd much prefer if people (in my field) universally adopted Grothendieck universes and tried to awkwardly dance around size issues like they still do so often
@Thorgott do it like Lurie and explain 3 different ways to handle size issues, one of which is "just ignore them," and then don't make precise which one you're going to use :D