Problems that appear in two or more problem collection

Stream: Formal conjectures

[Moritz Firsching]

There is some overlap between problem collections, for instance there are problems on Wikipedia that are also Erdős problems, or Erdős Problems that also appear in Ben Green's problem list.

How should we handle that? So far we have created files either only containing doc strings or repeating the theorem using type_of%. Now we could also use alias, see FC#1885 (and also FC#1627).

Even though this might be a bit of bike-shedding, perhaps it is good to think about how to do this best!

[Moritz Firsching]

All else being equal, I would favor the type_of% approach, because it seems flexible and works well with our category attributes