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2010 Fiscal Year Final Research Report

Multiflows and metrics

Research Project

  • PDF
Project/Area Number 20740054
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeSingle-year Grants
Research Field General mathematics (including Probability theory/Statistical mathematics)
Research InstitutionKyoto University

Principal Investigator

HIRAI Hiroshi  Kyoto University, 大学院・情報理工学系研究科, 講師 (20378962)

Project Period (FY) 2008 – 2010
Keywordsマルチフロー / メトリック / ネットワークフロー / 最大最小定理
Research Abstract

We studied multiflow problems in combinatorial optimization. We introduced and developed the tight-span duality theory, which extends the duality relationship between multiflows and metrics, a well-known duality since 70's. As a consequence, We solved Karzanov' s problem, one of important open problems in the literature, which asks a complete characterization for the class of multiflow problems admitting combinatorial min-max theorems and the discreteness of flows. This result is an important step toward a unified theory for multiflow problems.

  • Research Products

    (15 results)

All 2011 2010 2009 2008 Other

All Journal Article (5 results) (of which Peer Reviewed: 5 results) Presentation (10 results)

  • [Journal Article] The maximum multiflow problems with bounded fractionality2010

    • Author(s)
      Hiroshi Hirai
    • Journal Title

      The Proceedings of 42th ACM Symposium on Theory of Computing (STOC 2010) 115-120

    • Peer Reviewed
  • [Journal Article] T_x-approaches to multiflows and metrics, In : S.Iwata (ed.)2010

    • Author(s)
      Hiroshi Hirai
    • Journal Title

      Combinatorial Optimization and Discrete Algorithms, RIMS Kokyuroku Bessatsu 23

      Pages: 107-130

    • Peer Reviewed
  • [Journal Article] Metric packing for K_3+ K_32010

    • Author(s)
      Hiroshi Hirai
    • Journal Title

      Combinatorica 30

      Pages: 295-326

    • Peer Reviewed
  • [Journal Article] Tight spans of distances and the dual fractionality of undirected multiflow problems2009

    • Author(s)
      Hiroshi Hirai
    • Journal Title

      Journal of Combinatorial Theory B 99

      Pages: 843-868

    • Peer Reviewed
  • [Journal Article] Folder complexes and multiflow combinatorial dualities

    • Author(s)
      Hiroshi Hirai
    • Journal Title

      SIAM Journal on Discrete Mathematics, to appear

    • Peer Reviewed
  • [Presentation] 重み付き多品種流最大化問題2011

    • Author(s)
      平井広志
    • Organizer
      第7回組合せ論若手研究集会
    • Place of Presentation
      慶応大学日吉キャンパス
    • Year and Date
      2011-02-22
  • [Presentation] Tree metrics and edge-disjoint S-paths2010

    • Author(s)
      Hiroshi Hirai
    • Organizer
      Kyoto Prize Satellite Workshop
    • Place of Presentation
      東京工業大学大岡山キャンパス
    • Year and Date
      2010-11-18
  • [Presentation] The maximum multiflow problems with bounded fractionality2010

    • Author(s)
      Hiroshi Hirai
    • Organizer
      42th ACM Symposium on the Theory of Computing (STOC2010)
    • Place of Presentation
      Cambridge, USA
    • Year and Date
      2010-06-05
  • [Presentation] Half-integrality of node-capacitated multiflows and tree-shaped facility locations on trees2010

    • Author(s)
      平井広志
    • Organizer
      研究集会「最適化:モデリングとアルゴリズム」
    • Place of Presentation
      統計数理研究所,東京立川
    • Year and Date
      2010-03-24
  • [Presentation] Multicommodity flow problems with bounded fractionality2010

    • Author(s)
      平井広志
    • Organizer
      岡村治子先生退職記念研究集会
    • Place of Presentation
      甲南大学,兵庫
    • Year and Date
      2010-03-06
  • [Presentation] Bounded fractionality of multiflow feasibility problem for demand graph K3+K3 and other maximization problems2009

    • Author(s)
      Hiroshi Hirai
    • Organizer
      20th International Symposium on Mathematical Programming (ISMP 2009)
    • Place of Presentation
      Chicago, USA
    • Year and Date
      2009-08-27
  • [Presentation] Multiflow feasibility problem for demand graph K3+K32009

    • Author(s)
      Hiroshi Hirai
    • Organizer
      6th Japanese-Hungarian Symposium on Discrete Mathematics and Its Applications
    • Place of Presentation
      Budapest, Hungary.
    • Year and Date
      2009-05-17
  • [Presentation] Tight spans, metric labeling, and multicommodity flows2009

    • Author(s)
      Hiroshi Hirai
    • Organizer
      Workshop "Discovering Patterns in Biology"
    • Place of Presentation
      Chosun Spa Hotel, GyeongJu, Korea
    • Year and Date
      2009-03-21
  • [Presentation] 最大多品種流問題の双対有界分数性2008

    • Author(s)
      平井広志
    • Organizer
      日本オペレーションズリサー分数性,日本オペレーションズリサーチ学会秋季研究発表会
    • Place of Presentation
      札幌コンベンションセンター
    • Year and Date
      2008-09-11
  • [Presentation] T_x-approaches to multiflows and metrics2008

    • Author(s)
      Hiroshi Hirai
    • Organizer
      Kyoto RIMS Workshop "Combinatorial Optimization and Discrete Algorithms"
    • Place of Presentation
      京都大学数理解析研究所
    • Year and Date
      2008-06-10

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Published: 2012-02-13   Modified: 2016-04-21  

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