Such nanopublications express a causal (e.g. "A causes B"), spatio-temporal (e.g. "A is included in B"), or comparative (e.g. "A is larger than B") relation between the instances of two classes.
The subject and object are classes that are connected by the fact that their instances tend to have a particular relation.
The aspect of "tending to" is left underspecified; for more precise statements, use the super-pattern template instead.