Encoding messages in a discrete channel.

K is the process of converting one form of presenting information to another in order to ensure the convenience of its storage and transmission. The coding mapping Γ is the mapping of the set of words in some alphabet into the set of words in the same or another alphabet. The input character set is the input alphabet, the output set is the output. The use of the encoding map Γ to a word represented in the input alphabet is called encoding , and the encoding rule Γ itself is called a code.

Example: A = {p, q, r, s}, B = {a, b}. R (qprrs) = abaabababb.

A word made up of characters from the output alphabet is called a code combination. Codes that form code combinations of different lengths are called non-uniform , and uniform codes are called uniform . The length of code combinations of a uniform code is called code value. The process of reverse coding - decoding . The essence of decoding is that according to the existing code combination using the rule G, the input word is restored. G ^-1 (abaabababb) = qprrs. An important problem is the problem of uniqueness, i.e. the code must be such that any code combination is decoded into non-repeating words. Typically, the input alphabet is the symbols of natural language, mathematical operations, special characters ($,%). The characters of the output alphabet: 0 and 1.