OWL is an extension of RDF

 Hi,

In your document : http://www.w3.org/TR/owl-features/

We can find this :
3.1 OWL Lite RDF Schema Features
OWL can be viewed as an extension of a restricted view of the RDF language. This implies that every OWL document is an RDF document, but not all RDF documents are OWL documents. 

 I'm not very comfortable with the second sentence. It seems to me that "every RDF document is an OWL document, but not all OWL documents are RDF documents"

Thank you for all the work you're doing.

Rachida