What is the {human} for {student} of {Democritus}
Who was the understudy of Democritus?
Who was the student of Democritus?
SELECT DISTINCT ?e WHERE { resource:Democritus property:student ?e . ?e rdf:type ontology:human }
select distinct ?obj where { ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q41980> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P802> . ?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj . ?obj <http://www.wikidata.org/entity/P31> <http://wikidata.dbpedia.org/resource/Q5> } 
 select distinct ?obj where { wd:Q41980 wdt:P802 ?obj . ?obj wdt:P31 wd:Q5 } 
Protagoras Anaxarchus Metrodorus of Chios Nessas of Chios Hippocrates