The selection of a compression scheme shows that, in given limitations in open information systems, the lower limit at which compression occurs as a result of construction of iterative structures, is the four-digit coding system.
It suggests us to think that the fact that the codes constructed in the four-digit coding system will have a high value of the coefficient of compression. This result suggests that a four-letter alphabet coding, experimentally confirmed by the phenomenon of the genetic code. It is also shown its practical application value for the biological and natural systems, as well as - to explain, given the limitations of the phenomenon of short-term and long-term memory.