“…The theory of ultrametric spaces is closely connected with various directions of investigations in mathematics, physics, linguistics, psychology and computer science. Different properties of ultrametric spaces have been studied in [3,9,[18][19][20]22,30,31,39,[43][44][45][46][47][48][49][54][55][56]61,62]. Note that the use of trees and tree-like structures gives a natural language for description of ultrametric spaces [2, 6, 10, 17, 23, 24, 26-28, 33, 36-38, 49-51].…”