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Computational Results for Regular Difference Systems of Sets Attaining or Being Close to the Levenshtein Bound
Authors:Shoko Chisaki  Nobuko Miyamoto
Institution:1. Graduate School of Science and Technology, Tokyo University of Science, Noda, Japan;2. Department of Information Science, Tokyo University of Science, Noda, Japan
Abstract:Difference systems of sets (DSSs) are combinatorial structures arising in connection with code synchronization that were introduced by Levenshtein in 1971, and are a generalization of cyclic difference sets. In this paper, we consider a collection of m‐subsets in a finite field of prime order urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0001 to be a regular DSS for an integer m, and give a lower bound on the parameter ρ of the DSS using cyclotomic numbers. We show that when we choose urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0002‐subsets from the multiplicative group of order e, the lower bound on ρ is independent of the choice of urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0003 subsets. In addition, we present some computational results for DSSs with block sizes urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0004 and urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0005, whose parameter ρ attains or comes close to the Levenshtein bound for urn:x-wiley:10638539:media:jcd21512:jcd21512-math-0006.
Keywords:difference systems of sets  cyclotomic cosets  cyclotomic numbers
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