Am 09.01.2017 um 11:16 schrieb Peter F. Patel-Schneider:
Although there is no formal problem here, care does have to be taken when modelling entities that are to be considered as both classes and non-classes (or, and especially, metaclasses and non-metaclass classes). It is all too easy for even experienced modellers to make mistakes. The problem is worse when the modelling formalism is weak (as the Wikidata formalism is) and thus does not itself provide much support to detect mistakes. The problem is even worse when the modelling methodology often does not provide much description of the entities (as is the case in Wikidata).
That's what I meant by "problematic". I did not mean to say it's *wrong* per se.