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1990 Fiscal Year Final Research Report Summary

Algebraic Studies on Hadamard Matrices, Block Designs and Error-Correcting Codes

Research Project

Project/Area Number 01540086
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 代数学・幾何学
Research InstitutionMeijo University (1990)
Konan University (1989)

Principal Investigator

ITO Noboru  Meijo University, Department of Mathematics, Professor, 理工学部, 教授 (20151524)

Co-Investigator(Kenkyū-buntansha) FURUYA Mamoru  Meijo University, Department of Mathematics, Professor, 理工学部, 教授 (80076520)
TAGUTI Tomoyasu  Kokan University, Department of Applied Mathematics, Professor, 理学部, 教授 (30140388)
Project Period (FY) 1989 – 1990
KeywordsHadamard Tournament / Even Tournament / Regular Tournament / Cyclic Tournament / Hamming Weight / Nearly Triple Regular / 3-Blocks Intersection Number
Research Abstract

(1) We have shown that there exists a regular even tournament for every positive integer v such that v is congruentto 3 modulo 8.
(2) We have solved the existence problem for cyclic even tournaments. If v is congruent to 3 modulo 8, then a cyclic even tournament of order v exists if and only if 2 has a singly even order for every prime factor p of v. If v is congruent to 1 modulo 8, then a cyclic even tournament of order v exists if and only if 2 has an odd order for every prime factor p of v. In the second case an intimate relation with a binary cyclic code where the Hamming weight of every code word is a multiple of 4 exists.
(3) We have determined the largest number which may be the order of the automorphism group G of a cyclic tournament of order v and the structure of G in such a case.
(4) We have improved results of Alspach and Berggren concerning a tournament of order v whose automorphism group has the largest order. Namely we obtained necessary and sufficient conditions for v such that the group is a 3-group or (3, 5)-group.
(5) We together with Raposa in Manila, Philippines have shown that the 3-intersection number pair is unique for a nearly triply regular symmetric design of RH-type.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] N.Ito: "On Hadamard tournaments" Journal of Algebra. 131. 432-443 (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Ito: "On spectra of loubly regulor asymmetic ligraphs of RHーtype" Graphs and Combinatonis. 5. 229-234 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Ito: "On the nonーexistence of a nearly triply regular Hadamard 2ー(35,17,8)design" Mem. Konan Univ.Sci.Ser. 36. 111-113 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Ito: "Nearly triply regular Hadamard desigus and tournament" Mathematical Jowrnal of Okayama University.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Ito: "On 2ーothogonal tournaments" Discrete Mathematics(第2回グラフ理論国際会議で発表).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N.Ito: "On cyclic tournaments" Hokkaido Mathematical Journal.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] N. ITO: "On spectra of doubly regular asymmetric digraphs of RH-type." Graphs and Combinatorics. 5. 229-234 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. ITO: "On the non-existence of a nearly triply regular Hadamard 2-(35, 17, 8) design." Mem. Konan Univ. Sci. Ser. 36. 111-113 (1989)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. ITO: "On Hadamard tournaments." Journal of Algebra. 131. 432-443 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. ITO: "On 2-ortogonal tournaments" Discrete Mathematics.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. ITO: "On cyclic tournaments" Hokkaido Mathematical J.

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] N. ITO and B. RAPOSA: "Nearly triply regular symmetric designs of RH-type" Graphs and Combinatorics.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1993-08-12  

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