What is {participant of} of {Vladimir Putin} that is {point in time} is {1999-12-31} ?
did vladimir putin perticipate in 1999-12-31?
SELECT ?obj WHERE { wd:Q7747 p:P1344 ?s . ?s ps:P1344 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'1999')) }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q7747> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1344> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P585> <1999-12-31>
} 

In 1999-12-31, did Vladimir Putin perticipate?