THE MEDIAN FUNCTION ON TREES

Source abstract

A median of a sequence π = (x 1 , x 2 , …, x k ) of elements of a finite metric space (X, d) is an element x for which [Formula: see text] is minimum. The function with domain the set of all finite sequences on X and defined by Med(π) = {x | x is a median of π} is called the Median function on X. In this note, an axiomatic characterization of the median function on finite trees is given.