Codes asynchrones

On the construction of statistically synchronizable codes

“…A code is called statistically synchronizable for a given source if lim S!1 P rfs Sg = 1: The statistical synchronizability property of the code implies the occurrence, in the input of the decoder, of a sequence of codewords which allows the decoder to recover synchronization 4-6], 15], 16], [18][19][20][21][22][23][24][25][26][27]. Such sequences are called synchronizing.…”

Noncommutative factorization of variable-length codes

“…For other work on the factorization conjecture, see Restivo [22], C6sari [5], Perrin [18], Bo~ [3] and Perrin and Schfitzenberger [19]. In the latter is shown that, for any code C, the quotient (~o(C)-1)/(~o(A)-1) has nonnegative coefficients if and only if C is commutatively equivalent to a prefix code (i.e.…”

On a complete set of operations for factorizing codes

“…The class of factorizing codes was showed to be closed under composition and under substitution, another operation which was initially considered for finite prefix maximal codes in [3] and subsequently defined for factorizing codes in [2]. This operation is based on the idea which frequently recurs in the literature on codes, of changing a word w with a set of words constructed starting from w [6,12,30,41]. Precisely, given factorizing codes C = P (A − 1)S + 1, C = P (A − 1)S + 1 and w ∈ C , C = (P + wP )(A − 1)S + 1 is again a factorizing code which is called a substitution of C and C by means of w [1,2].…”