Abstract
The normative version of RDFS gives non-standard (intensional) interpretations to some standard notions such as classes and properties. In this paper we develop the extensional semantics for the RDFS vocabulary, which surprisingly preserves the simplicity and computational complexity of deduction of the intensional case. This result will impact current implementations in a positive sense, as reasoning in RDFS will follow common set-based intuitions and be compatible with OWL extensions; moreover, the rule system that we present is easily embeddable in existing libraries such as Jena.