English

Hadamard matrices related to a certain series of ternary self-dual codes

Combinatorics 2023-03-28 v1 Information Theory math.IT

Abstract

In 2013, Nebe and Villar gave a series of ternary self-dual codes of length 2(p+1)2(p+1) for a prime pp congruent to 55 modulo 88. As a consequence, the third ternary extremal self-dual code of length 6060 was found. We show that the ternary self-dual code contains codewords which form a Hadamard matrix of order 2(p+1)2(p+1) when pp is congruent to 55 modulo 2424. In addition, it is shown that the ternary self-dual code is generated by the rows of the Hadamard matrix. We also demonstrate that the third ternary extremal self-dual code of length 6060 contains at least two inequivalent Hadamard matrices.

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Cite

@article{arxiv.2205.15498,
  title  = {Hadamard matrices related to a certain series of ternary self-dual codes},
  author = {Makoto Araya and Masaaki Harada and Koji Momihara},
  journal= {arXiv preprint arXiv:2205.15498},
  year   = {2023}
}

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15 pages