Was M1 a person influenced by a person and influenced by M2 and M3
SELECT count(*) WHERE {
?x0 a ns:people.person .
M1 a ns:people.person .
M1 ns:influence.influence_node.influenced_by ?x0 .
M1 ns:influence.influence_node.influenced_by M2 .
M1 ns:influence.influence_node.influenced_by M3
}