Around simple dynamical systems. Induced joinings and multiple mixing (Q1972733)

The author proves that 2-fold mixing automorphisms with minimal self-joinings of order 2 have minimal self-joinings of all orders; an order 3 quasisimple action is quasi-simple of all orders. He also shows that any 2-simple action commuting with an uncountable family of mixing automorphisms is simple of all orders.