A median of a sequence ï° = x1, x2, … , xk of elements of a finite metric space (X, d ) is an element x for which  1 ≤ I ≤ k d(x, xi) is minimum. The function M with domain the set of all finite sequences on X and defined by M(ï°) = {x: x is a median of ï°} is...

A mean of a sequence π = (x1, x2, . . . , xk) of elements of a finite metric space (X, d) is an element x for which is minimum. The function Mean whose domain is the set of all finite sequences on X and is defined by Mean(π) = { x | x is a mean of π } is called the mean function on...