question: Did M1 and M3 influence a person and marry M2
query: SELECT count(*) WHERE {
  ?x0 a ns:people.person .
  FILTER ( M1 != M2 ) .
  FILTER ( M3 != M2 ) .
  M1 ns:influence.influence_node.influenced ?x0 .
  M1 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses M2 .
  M3 ns:influence.influence_node.influenced ?x0 .
  M3 ns:people.person.spouse_s/ns:people.marriage.spouse|ns:fictional_universe.fictional_character.married_to/ns:fictional_universe.marriage_of_fictional_characters.spouses M2
  }