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An improvement of the Ivanov bound

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Abstract

Let Γ be a distance-regular graph of diameterd, valencyk andr=max{i|(c i ,b i )=(c 1,b 1)}. In this paper, we prove that

$$d< \frac{1}{2}k^3 r.$$

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Authors and Affiliations

  1. Division of Mathematical Sciences, Osaka Kyoiku University, Kashiwara, 582, Osaka, Japan

    Akira Hiraki

  2. Graduate School of Mathematics, Kyushu University, 812, Fukuoka, Japan

    Jack Koolen

Authors
  1. Akira Hiraki
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  2. Jack Koolen
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Hiraki, A., Koolen, J. An improvement of the Ivanov bound. Annals of Combinatorics 2, 131–135 (1998). https://doi.org/10.1007/BF01608483

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  • DOI: https://doi.org/10.1007/BF01608483

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