Types are read off the nanopublication itself, so nothing needs registering. A type stated on the nanopublication in its publication info counts, whether as a plain type or with npx:hasNanopubType. So does every type of a thing the nanopublication introduces, describes or embeds, and every type of its assertion. Two shortcuts cover simple assertions: if all statements have the same subject, that subject's types count, and if all use the same predicate, that predicate itself becomes the type — which is why a one-statement nanopublication saying \"X is relevant for Y\" is filed under \"is relevant for\".