Question: What locations where President Barack Obama has lived have a population below 2851268?
Answer(s):
answer: Washington, D.C.
answer: Honolulu
answer: Chicago

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ns:m.02mjmr)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
ns:m.02mjmr ns:people.person.places_lived ?y .
?y ns:people.place_lived.location ?x .
FILTER(NOT EXISTS {?y ns:people.place_lived.end_date ?sk0} || 
EXISTS {?y ns:people.place_lived.end_date ?sk1 . 
FILTER(xsd:datetime(?sk1) >= "2015-08-10"^^xsd:dateTime) })
FILTER(NOT EXISTS {?y ns:people.place_lived.start_date ?sk2} || 
EXISTS {?y ns:people.place_lived.start_date ?sk3 . 
FILTER(xsd:datetime(?sk3) <= "2015-08-10"^^xsd:dateTime) })
?x ns:topic_server.population_number ?num .
FILTER (xsd:integer(?num) < 2851268) . 
}