Forall ?x ?z ?y (
      ?x["http://example.com/RDF/ex#P"^^rif:iri->?z] :- And(
       ?x["http://example.com/RDF/ex#P"^^rif:iri->?y]
       ?y["http://example.com/RDF/ex#P"^^rif:iri->?z]  ))