PPT Slide
Replace all anonNodes in a document E by urirefs from a set V (disjoin t from vocab(E))
1. sk(E) entails E (obviously)
2. E probably doesn’t entail sk(E)….BUT
3. If sk(E) entails F and F doesn’t contain any vocabulary from V, then E entails F
Proof: Suppose I satisfies E. Then there is mapping A in anon(E) such that I+A satisfies set(E). If sk(x) is the uriref that replaces the anonNode x, then define I’ to be like I except I’(sk(x))=A(x), then clearly I’ satisifes sk(E). sk(E) entails F, so I’ satisfies F, so I’/vocab(F) satisfies F. But vocab(F) does not intersect V, so I’/vocab(F)=I; whence, I satisfies F. QED.
So, as far as V-free expressions are concerned, E and sk(E) entail the same things. So (with the no-V-provision), asserting sk(E) and asserting E amount to making the same assertion.