https://w3id.org/framester/conceptnet5/data/en/propositional_calculus <https://w3id.org/framester/conceptnet5/schema/IsA> <https://w3id.org/framester/conceptnet5/data/en/logical_calculus.n> <https://w3id.org/framester/conceptnet5/schema/Synonym> <https://w3id.org/framester/conceptnet5/data/en/propositional_logic> risorse dalla linked data cloud