Explanation for reification in RDF

Question

I am have understand the basics of reification in RDF. Two clearly explanations are given here: explanation 1 and explanation 2. If you observe carefully, actually we can present in the sentence "Earth is round" RDF triple where as "Scientist discovered, Earth is round" can be presented using reification. While studying reification, I have found that it also says that it can represent sentence like: (using reified triples)

"John believes the world is round and Jane believes the world is flat". or "Marconi claimed to have invented the radio, but so did Bose."

Can anyone please give a simple and clear explanation(like the given links) how this can be done? Thanks.

Lester

Answer 1

Both examples can be simply expressed in two separate reifications each. The first example contains two separate statements, one believed by Jane, the other believed by John. Using reification (in Turtle syntax) to express this would yield something like this:

:John :believes [ a rdf:Statement;  
                  rdf:subject :earth ; 
                  rdf:predicate :shape ; 
                  rdf:object :round ] .
:Jane :believes [ a rdf:Statement;  
                  rdf:subject :earth ; 
                  rdf:predicate :shape ; 
                  rdf:object :flat ] .

The second sentence can be expressed in a similar way, as two separate reifications. Marconi believes one thing, Bose believes something else.

Amory

Spot on! It's worth pointing out though, that the graph does not contain the triples :earth :shape :round or :earth :shape :flat, and querying, e.g., with SPARQL, for :earth :shape ?shape won't produce the shapes that people believe the world is. I'm only pointing this out, because sometimes people expect reified triples to still be triples in the graph, but they're not. – Informed

Answer 2

An alternative approach for this is to use the singleton property approach. In that, we create two singleton properties

:earth :shape#1 :round .

:shape#1 rdf:singletonPropertyOf :shape .

:John :believes :shape#1 .

:earth :shape#2 :flat .

:shape#2 rdf:singletonPropertyOf :shape .

:Jane :believes :shape#2 .

Freehearted