 Reichenbach introduced the terminology of screening off to describe a particular type of probabilistic relationship. If \(\PP(E \mid A \amp C) = \PP(E \mid C)\), then C is said to screen A off from E. When \(\PP(A \amp C) \gt 0\), this equality is equivalent to \(\PP(A \amp E \mid C) = \PP(A \mid C) \times \PP(E \mid C)\); i.e., A and E are probabilistically independent conditional upon C.