[71] f(x) → b (x → a). ⇔ f_i(x) → b_i (x → a) for all 1 ≦ i ≦ m, provided that f(x) = (f_1(x), . . . f_m(x)) and b = (b_1, . . . b_m).

https://www.evernote.com/shard/s29/sh/d691b66b-6f42-41a5-8036-7dc14212f8b0/059b33aa8a475513edb54630e0f306da