Such nanopublications express a causal (e.g. "A caused B"), spatio-temporal (e.g. "A is included in B"), or comparative (e.g. "A is larger than B") relation between two things.

Note that the left-hand side element (subject) as well as the right-hand side one (object) need to be individuals that exist just once, like the French revolution or the Internet, and not classes that stand for a set of things, like city or headache.