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Research on the minimum ai'ea of convex lattice polygons and multiply intersecting families

Research Project

Project/Area Number 14540131
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field General mathematics (including Probability theory/Statistical mathematics)
Research InstitutionUniversity of the Ryukyus

Principal Investigator

TOKUSHIGE Norihide  University of the Ryukyus, College of Education, Associate Professor, 教育学部, 助教授 (00217481)

Project Period (FY) 2002 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥1,700,000 (Direct Cost: ¥1,700,000)
Keywordsdiscrete gepmetry / extremal set theory / lattice point / intersecting family / random walk / 極地集合論 / random walk
Research Abstract

Let A(n) be the-minimum area of convex Lattice n-gon. We have proved that lim A(n)/n^3 exists, and moreover this value is very close to 0.0185067, which is a little bit less than 1/54 which comes from an obvious construction. This result is accepted by Combinatorica.
A family of subsets is called r-wise t-intersecting if any r edges have at least t common vertices. A family of subsets is called Sperner if it contains no inclusion relationship among subsets. We have determined the maximum size of 4-wise 2-intersecting Sperner families. Then we moved on 3-wise case, which was much more-difficult than 4-wise case. Using random walk method, we finally obtained Erdos-Ko-Rado type inequality for 3-wise 2-intersecting families, and then we succeeded to determine the maximum size of 3-wise 2-intersecting Spernar families. We have wrote two papers on this topic, one appears in J.Comb.Theory, the other has been submitted to the same journal.
I did three lectures about the above results as an invited talk at ZiF research year, opening conference "General theory of information transfer and combinatorics", ISM Symposium "Statistics, Combinatorics and Geometry" and Renyi Institute "Workshop on extremal combinatorics."

Report

(3 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • Research Products

    (19 results)

All Other

All Publications (19 results)

  • [Publications] P.Frankl, N.Tokushige: "Weighted multiply intersecting families"Weighted multiply intersecting families. 40. 287-291 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "The game of n-times nim"Discrete Math.. 260. 205-209 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted 3-wise 2-intersecting families"J.Comb.Theory (A). 100. 94-115 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Y.Eagawa, H.Enomoto, N.Tokushige: "Graph decompositions through prescribed vertices without isolates"Ars Combinaotira. 62. 189-205 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted non-trivial multiply intersecting families"(印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] I.Barany, N.Tokushige: "The minimum area of convex lattice n-gons"(印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted multiply intersecting families"Studia Sci.Math.Hungarica. Vol.40. 287-291 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "The game of n-times nim"Discrete Math.. Vol.260. 205-209 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted 3-wise 2-intersecting families"J.Comb.Theory(A). Vol.62. 189-205 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] Y.Egawa, H.Enomoto, N.Tokushige: "Graph decompositions through prescreibed vertices without isolates"Ars Combinatoria. Vol.62. 189-205 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted non-trivial multiply intersecting families"Combinatorica. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] I.Barany, N.Tokushige: "The minimum area of convex lattice n-gons"Combinatorica. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] P.Frankl, N.Tokushige: "Weighted multiply intersecting families"Studia Sci.Math.Hungarica. 40. 287-291 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] P.Frankl, N.Tokushige: "The game of n-times nim"Discrete Math. 260. 205-209 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] P.Frankl, N.Tokushige: "Weighted non-trivial multiply intersecting families"Combinatorica. (発表予定).

    • Related Report
      2003 Annual Research Report
  • [Publications] I.Barany, N.Tokushige: "The minimum area of convex lattice n-gons"Combinatorica. (発表予定).

    • Related Report
      2003 Annual Research Report
  • [Publications] N.Tokushige, P.Frankl: "Weighte 3-wise 2-intersecting families"J.Combin.Theory Ser.A. 100. 94-115 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] N.Tokushige, P.Frankl: "The game of n-times nim"Discrete Math.. 260. 205-209 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] N.Tokushige, Y.Egawa, H.Enomoto: "Graph decompositions through prescribed vertices without isolates"Ars Combin.. 62. 189-205 (2002)

    • Related Report
      2002 Annual Research Report

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Published: 2002-04-01   Modified: 2016-04-21  

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