互相的,交替的,交換的
Commutative \Com*mut"a*tive\, a. [CF. F. commutatif.] Relative to exchange; interchangeable; reciprocal. -- {Com*mut"a*tive"ly}, adv. Rich traders, from their success, are presumed . . . to have cultivated an habitual regard to commutative justice. --Burke.
commutative adj : of a binary operation; independent of order; as in e.g. "a x b = b x a"