Who was employed by M1 , was employed by M2 , and was employed by a company that employed M4
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:people.person .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company ?x1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x1 a ns:business.employer .
?x1 ns:business.employer.employees/ns:business.employment_tenure.person M4
}