295,175 research outputs found

    A note on binary completely regular codes with large minimum distance

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    We classify all binary error correcting completely regular codes of length nn with minimum distance δ>n/2\delta>n/2.Comment: 4 page

    Distance-regular graphs

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    This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the monograph 'BCN' [Brouwer, A.E., Cohen, A.M., Neumaier, A., Distance-Regular Graphs, Springer-Verlag, Berlin, 1989] was written.Comment: 156 page

    Families of nested completely regular codes and distance-regular graphs

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    In this paper infinite families of linear binary nested completely regular codes are constructed. They have covering radius ρ\rho equal to 33 or 44, and are 1/2i1/2^i-th parts, for i{1,,u}i\in\{1,\ldots,u\} of binary (respectively, extended binary) Hamming codes of length n=2m1n=2^m-1 (respectively, 2m2^m), where m=2um=2u. In the usual way, i.e., as coset graphs, infinite families of embedded distance-regular coset graphs of diameter DD equal to 33 or 44 are constructed. In some cases, the constructed codes are also completely transitive codes and the corresponding coset graphs are distance-transitive

    Diagonally Neighbour Transitive Codes and Frequency Permutation Arrays

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    Constant composition codes have been proposed as suitable coding schemes to solve the narrow band and impulse noise problems associated with powerline communication. In particular, a certain class of constant composition codes called frequency permutation arrays have been suggested as ideal, in some sense, for these purposes. In this paper we characterise a family of neighbour transitive codes in Hamming graphs in which frequency permutation arrays play a central rode. We also classify all the permutation codes generated by groups in this family
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