Question: When did Iannis Xenakis marry Francoise Xenakis?
Paraphrase: When did Iannis and Francoise Xenakis wed?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q152880 p:P26 ?s . ?s ps:P26 wd:Q3086635 . ?s pq:P580 ?value}