question: What employee of M0 and M1 was employed by M2 , employed by M3 , M4 , and M5 , and employed by M6
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M4 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M5 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M6
  }