[gryn]

you can have a date_start and date_end to handle this ambiguity. but yes the complexity lies in the interpreter/reasoner that has to deal with these facts and evolution of this (meta)schema.

But rdf style and labeled property graph data modeling approach have multiple ways of dealing with this.

[babelchips]

The way Datomic handles facts, accumulating them and providing point-in-time queries, is very effective.

Facts can contradict each other. Old facts are not lost. Querying requires a notion of time - “as of”.

[zcw100]

It's a combination of reification and bitemporal modeling.

[jaygray0919]

Correctomundo. See RDF-Star for progress about state-in-time. During summer 2022 there was extensive discussion/consideration in the W3C working group about different state-conditions.