Question: Do Harry and William, Princes of Wales, have the same mother?
SPARQL:
PREFIX dbp: <http://dbpedia.org/property/> ASK WHERE { <http://dbpedia.org/resource/Prince_William,_Duke_of_Cambridge> dbp:mother ?x . <http://dbpedia.org/resource/Prince_Harry_of_Wales> dbp:mother ?y . FILTER (?x = ?y) }