23/08/29 09:21:28.03 f5A/er/P0.net
以下は、Michael Spivak著『Calculus Fourth Edition』にあるベクトルについての説明です。
Suppose that v is a point in the plane; in other words, v is a pair of numbers v = (v1, v2).
For convenience, we will use this convention that subscripts indicate the first and second pairs of a point that has been described by a single letter.
Thus, if we mention the points w and z, it will be understood that w is the pair (w1, w2), while z is the pair (z1, z2).
なぜ、「the first and second pair」ではなく、「the first and second pairs」とpairが複数形になっているのでしょうか？