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arXiv · 1509.01326

On the largest subsets avoiding the diameter of $(0,\pm 1)$-vectors

Saori Adachi·Hiroshi Nozaki
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Abstract

Let $L_{mkl}\subset \mathbb{R}^{m+k+l}$ be the set of vectors which have $m$ of entries $-1$, $k$ of entries $0$, and $l$ of entries $1$. In this paper, we investigate the largest subset of $L_{mkl}$ whose diameter is smaller than that of $L_{mkl}$. The largest subsets for $m=1$, $l=2$, and any $k$ will be classified. From this result, we can classify the largest $4$-distance sets containing the Euclidean representation of the Johnson scheme $J(9,4)$. This was an open problem in Bannai, Sato, and Shigezumi (2012).

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Saori Adachi, Hiroshi Nozaki. 2015-11-15. On the largest subsets avoiding the diameter of $(0,\pm 1)$-vectors. https://arxiv.org/abs/1509.01326

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