https://w3id.org/framester/conceptnet5/data/en/gaussian_integer <https://w3id.org/framester/conceptnet5/schema/IsA> <https://w3id.org/framester/conceptnet5/data/en/algebraic_integer.n> <https://w3id.org/framester/conceptnet5/data/en/quadratic_integer.n> <https://w3id.org/framester/conceptnet5/data/en/complex_number.n> risorse dalla linked data cloud