On 08/05/13 02:28, Owen Stephens wrote:I'm not quite sure what you mean by "could not be expressed" Such use cases are readily expressed using the XPointer family of schemes. The best introduction to them I'm aware of is at http://wiki.tei-c.org/index.php/XPointer Members of the family exists in a variety of states of implementation and standardisation.
1) A highlighted span of text. There is an obvious target segment of a
resource (the object), but there is no body/comment (the subject). As a
triple must have a subject, this could not be expressed. A second
example of this would be a bookmark where the body is also implicit.
The W3C XPointer scheme at http://www.w3.org/TR/xptr-xpointer/ can point to any set of things pointable to by a single XPath 1.0 expression.2) An annotation that refers to multiple segments of a resource,
multiple resources or multiple segments of multiple resources. In this
case there would be multiple objects, which is also not possible to be
expressed in RDF.