@jens As @thisismissem points out, schema.org is not really specifying but suggesting types to be used, same with sdo-types as domain/range. If you want constraints you must define them yourself with Shex/Shacl or JSON Schema. For AMB, a schema.org-based metadata profile for educational resources on the web we chose JSON-LD plus a normative JSON Schema so that also people unfamiliar with RDF can easily use it: https://w3id.org/kim/amb/20231019 (German) JSON Schema: https://w3id.org/kim/amb/20231019/schemas/schema.json