Concept
Johnson bound
Concepts associés (4)
Griesmer bound
In the mathematics of coding theory, the Griesmer bound, named after James Hugo Griesmer, is a bound on the length of linear binary codes of dimension k and minimum distance d. There is also a very similar version for non-binary codes. For a binary linear code, the Griesmer bound is: Let denote the minimum length of a binary code of dimension k and distance d. Let C be such a code. We want to show that Let G be a generator matrix of C. We can always suppose that the first row of G is of the form r = (1, ...
Plotkin bound
In the mathematics of coding theory, the Plotkin bound, named after Morris Plotkin, is a limit (or bound) on the maximum possible number of codewords in binary codes of given length n and given minimum distance d. A code is considered "binary" if the codewords use symbols from the binary alphabet . In particular, if all codewords have a fixed length n, then the binary code has length n. Equivalently, in this case the codewords can be considered elements of vector space over the finite field .
Singleton bound
In coding theory, the Singleton bound, named after Richard Collom Singleton, is a relatively crude upper bound on the size of an arbitrary block code with block length , size and minimum distance . It is also known as the Joshibound. proved by and even earlier by . The minimum distance of a set of codewords of length is defined as where is the Hamming distance between and . The expression represents the maximum number of possible codewords in a -ary block code of length and minimum distance .
Code parfait et code MDS
Les codes parfaits et les codes à distance séparable maximale (MDS), sont des types de codes correcteurs d'erreur. Un code correcteur est un code permettant au récepteur de détecter ou de corriger des altérations à la suite de la transmission ou du stockage. Elle est rendue possible grâce à une redondance de l'information. Un code est dit parfait s'il ne contient aucune redondance inutile. Le concept correspond à un critère d'optimalité. Un code est dit MDS s'il vérifie un autre critère d'optimalité s'exprimant dans le contexte des codes linéaires.