A. J. van Zanten

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In this paper, we present some results concerning a decomposition of binary self-dual codes having an automorphism of an order which is the product of two odd prime numbers. These results are applied to construct self-dual [72,36,12] codes with an automorphism of order 15. Furthermore, it is proved that the automorphism group of a putative binary extremal(More)
A linear code E? is said to he in minimal-change order if each codeword differs from its predecessor by a word of minimum weight. A rule is presented to construct such an order in case that i? has a basis of codewords with minimum weight. Some consequences concem-ing the ranking and separability in 5 F are mentioned. It is well known that the set of all(More)
1229 compression of files of information retrieval systems. With this application in mind, bounds on the average codelength of an alphabetical code were studied. The major results of this correspondence are as follows. 1) A necessary and sufficient condition for the existence of a 2) An upper bound for Lopt (the average codelength of the binary alphabetical(More)
In this correspondence, we discuss a modified version of a method due to Bakos and, independently, to Robinson and Cohn for the construction of Gray sequences. We make use of this construction to prove the existence of so-called balanced cyclic half Gray sequences. Furthermore, we discuss a specific type of counting sequences, called maximum counting(More)