Availability:
:- use_module(library(semweb/rdf11)). [nondet]rdf_has(?S, 
+P, ?O)
[nondet]rdf_has(?S, 
+P, ?O)inverse_of and
symmetric. See rdf_set_predicate/2.Availability:
:- use_module(library(semweb/rdf_db)). [nondet]rdf_has(?Subject, 
+Predicate, ?Object)
[nondet]rdf_has(?Subject, 
+Predicate, ?Object)rdf(Subject, Predicate, Object) is 
true exploiting the rdfs:subPropertyOf predicate as well as inverse 
predicates declared using rdf_set_predicate/2 
with the
inverse_of property.