The W3C Provenance Working Group has published the First Public Working Draft of The PROV Ontology: Model and Formal Semantics. The PROV Ontology (also known as PROV-O) encodes the PROV Data Model in the OWL2 Web Ontology Language (OWL2). The PROV ontology consists of a set of classes, properties, and restrictions that can be used to represent provenance information. The PROV ontology can also be specialized to create new classes and properties for modeling provenance information specific to different domain applications. The PROV ontology supports a set of entailments based on OWL2 formal semantics and provenance specific inference rules. The PROV ontology is available for download as a separate OWL2 document.