rdfs:subClassOf – every instance of the subclass is an instance of the superclass.
rdfs:subClassOf
ex:Car rdfs:subClassOf ex:MotorVehicle . ex:Bus rdfs:subClassOf ex:MotorVehicle . ex:MyBlueVWGolf a ex:Car .
Excerpt from the products vocabulary of the Product Data Demo package.
weaker semantics, simpler reasoning → stronger semantics, harder or undecidable reasoning