Made as simple as possible, but not simpler.
Indexing Identifiers
Indexing identifiers is key to disambiguating entities. Wikipedia has disambiguation pages.
Validating Traces — Syntactically, Semantically, and Situationally
How do you validate a reified trace of digital-object provenance?
A Disconnect Between FAIR Infrastructure Devs and Product Devs
Rory Macneil nails it:1 This seems to me to be a really important problem.
Validating Translation
Given a representation of (meta)data that dcterms:conformsTo some data profile, you may wish to translate it to another data profile.