error in Semantics document

The following characterization of simple entailment is incorrect:

	The interpolation lemma completely characterizes simple RDF
	entailment in syntactic terms. To tell whether a set of RDF graphs
	entails another, find a subgraph of their merge and replace names
	by blank nodes to get the second. 

Consider RDF Graph A

	 ex:s ex:p ex:o .

and RDF Graph B

	ex:s ex:p _:b .
	ex:s ex:p _:c .

A simple entails B but this entailment does not fit the characterization
above. 

Peter F. Patel-Schneider
Bell Labs Research
Lucent Technologies