Optimal code
The term optimal code occurs in coding theory .
definition
Let n , d and q be natural numbers . A block code C of length n over a q -nary character set with a minimum spacing d is called optimal if the number of code words of C among all codes with these parameters is maximum. The number of code words of an optimal code is denoted by A q ( n , d ).
The determination of A q ( n , d ) for given parameters n , d and q is usually very difficult. In many cases only lower and upper bounds are known, which are often far apart.