https://w3id.org/framester/conceptnet5/data/en/mathematical_structure <https://w3id.org/framester/conceptnet5/schema/RelatedTo> <https://w3id.org/framester/conceptnet5/data/en/ring> <https://w3id.org/framester/conceptnet5/data/en/field> <https://w3id.org/framester/conceptnet5/data/en/group> <https://w3id.org/framester/conceptnet5/data/en/topological_space> <https://w3id.org/framester/conceptnet5/data/en/algebraic_structure> risorse dalla linked data cloud