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Hakata Workshop;Winter Meeting 2019 の履歴(No.4)


Hakata Workshop; Winter Meeting 2019

〜Discrete Mathematics and its Applications〜

 

Our purpose of this meeting is giving an opportunity to make a speech and to communicate with researchers who study various fields not only Combinatorics.

Further information is available from the organizers below.

Organizers

  • Yoshihiro Mizoguchi (Kyushu University),
  • Tetsuji Taniguchi (Hiroshima Institute of Technology),
  • Osamu Shimabukuro (Nagasaki University),
  • Makoto Tagami (Kyushu Institute of Technology),
  • Hirotake Kurihara (Kitakyushu National College of Technology),
  • Shuya Chiba (Kumamoto University),
  • Tsuyoshi Miezaki (University of the Ryukyus).

Supported by

Date

February 21, 2019

Location

Kyushu University (see https://www.kyushu-u.ac.jp/en/campus/ito/ )

Program

Abstract

Asuka TAKATSU

  • Title: Convergence of combinatorial Ricci flows to degenerate circle patterns
  • Abstract: On a connected, oriented, closed surface, a circle pattern metric determines a geometric structure (Riemannian metric of constant curvature) from a topological structure (weighted triangulation). A criterion for the existence of a circle pattern metric on a surface of nonpositive Euler characteristic was first proved by Thurston. Chow–Luo gave the algorithm, so-called the combinatorial Ricci flow, to find circle pattern metrics. Chow–Luo raised some questions about the combinatorial Ricci flow, one of which is to investigate the combinatorial Ricci flow when a circle pattern metric does not exist. In my talk, I address this question.

Makoto Tagami

  • Title: Harmonic Index t-design in Hamming Schemes
  • Abstract: The notion of harmonic index (or simply HI) spherical design was introduced as a finite set on a sphere in the form extending the notion of usual spherical designs by Bannai-Okuda-T (2015). They studied about a Fisher type inequality and construction for HI spherical design and argued about the non-existence of tight HI spherical designs. While Zhu-Bannai-Bannai-Ikuta-Kim(2017) reintroduced the notion of HI $t$-design in symmetric association schemes and they studied about HI $t$-designs in binary Hamming schemes. In this talk, we will study them in Hamming scheme H(n,q) for arbitrary q following BOT and ZBBIK .