a. 交替的, 交换的

[法] 交换的, 代替的, 互相的

[ adj ]
(of a binary operation) independent of order; as in e.g.
<adj.all>
a x b = b x a

Commutative \Com*mut"a*tive\, a. [CF. F. commutatif.]
1. 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.

2. (Math.) having the property of {commutativity}.
[PJC]