PREFIX  jfn:  <java:com.hp.hpl.jena.query.function.library.>
PREFIX  jx:   <java:com.hp.hpl.jena.query.extension.library.>
PREFIX :      <http://example/>

SELECT ?x ?p ?v
{
    ?x ?p ?v .
    EXT jx:clump(?v)
    EXT jx:clump(?p)

##     EXT jx:group(?v) 
##     EXT jx:traceGroup()
##     EXT jx:group(?p) 
##     EXT jx:traceGroup()

}
## ORDER BY ?v ?p