Popular RDF vocabularies represented in RDFS include:  An entailment regime defines by using RDFS (or OWL, etc.) not only which entailment relation is used, but also which queries and graphs are well-formed for the regime. The RDFS entailment is a standard entailment relation in the semantic web. For example, the following declares that 'Dog1 is an animal','Cat1 is a cat', 'Zoos host animals' and 'Zoo1 hosts the Cat2' :  ex:dog1 rdf:type ex:animal ex:cat1 rdf:type ex:cat zoo:host rdfs:range ex:animal ex:zoo1 zoo:host ex:cat2   But this graph is not well formed because the system can not guess that a cat is an animal. We have to add 'Cats are animals' to do a well-formed graph with :  ex:cat rdfs:subClassOf ex:animal   Here is a correct example: If your triplestore (or RDF database) implements the regime entailment of RDF and RDFS, the SPARQL query as follows (the keyword "a" is equivalent to rdf:type in SPARQL):  PREFIX ex:  SELECT ?animal WHERE Gives the following result with "cat1" in it because the Cat's type inherits of Animal's type: