“…For other applications, also see [17]. In geometric approximation theory, asymmetric norms proved to be useful in many problems (see, for example, [4], [6], [27], [29], and [68]). Asymmetric distances also appear naturally in approximation theory (in particular, in problems of best one-sided approximations), serving as a 'bridge' between best approximation and best one-sided approximation.…”