The RDFS Reasoner is a framework that enables reasoning over RDFS ontologies and that uses IRIS as underlying reasoning engine.
The RDFS Reasoner implementation is based on the work described in RDF and Logic: Reasoning and extension.. The paper explores the various kinds of RDF entailment in F-Logic. It shows, amongst others, that the embeddings of simple, RDF and RDFS entailment fall in the Datalog fragment of F-Logic.
The RDFS Reasoner translates ontology descriptions in RDFS to F-Logic molecules and rules. It uses IRIS as underlying generic Datalog reasoning component and therefore uses a facade that mediates between its internal representation and the IRIS specific representation.
The RDFS Reasoner currently supports the simple, RDF, RDFS and extensional RDFS (eRDFS) entailment regimes and allows WSML conjunctive queries as queries.
You can download a combined package containing both the RDFS Reasoner framework and IRIS at the RDFS Reasoner website.