question: What actor of M1 and M2 was a producer of M0
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 ns:film.actor.film/ns:film.performance.character M1 .
  ?x0 ns:film.actor.film/ns:film.performance.character M2 .
  ?x0 ns:film.producer.film|ns:film.production_company.films M0
  }