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Set theoretic multiverse and large cardinal axioms

Research Project

Project/Area Number 18K03403
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 12030:Basic mathematics-related
Research InstitutionWaseda University

Principal Investigator

Usuba Toshimichi  早稲田大学, 理工学術院, 教授 (10513632)

Project Period (FY) 2018-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Keywords巨大基数公理 / 集合論的多元宇宙 / 集合論的地質学 / 集合論的位相空間論 / ジェネリック巨大基数 / 巨大基数 / list chromatic number / 反映原理 / 集合論多元宇宙 / tightness number / 強コンパクト基数 / symmetric extension / リンデレフ空間 / 強制法
Outline of Final Research Achievements

We studied set-theoretic multiverse, in particular the structure of the entire multiverse under the large cardinal axiom, and obtained the following results: 1. If there exists a large cardinal such as an extendible cardinal, there exists an inner model that is invariant with respect to the forcing method. 2. Even in the absence of the Axiom of Choice, all ground models are uniformly definable if there are enough large cardinals, and thus it is possible to develop a multiverse theory without the Axiom of Choice. 3. Symmetric extension is a generalization of the forcing extension. We showed that all symmetric grounds are uniformly definable, and thus it is possible to develop a more extensive multiverse theory including the symmetric extensions.

Academic Significance and Societal Importance of the Research Achievements

強制法の発展により様々な数学の宇宙が構成可能であることが判明し、それにより強制拡大宇宙の総体である集合論的多元宇宙の研究が近年活発に行われている。本研究では、申請者が証明した多元宇宙理論の基本定理である「基礎モデルの下向きの有向性」をさらに発展させることで、巨大基数公理が多元宇宙理論に及ぼす影響を明らかにし、巨大基数が集合の宇宙の総体に予想しない形で影響を及ぼすことを明らかにした。また、選択公理の欠如のもとでも、巨大基数公理のもとでは多元宇宙理論が展開可能であることを示し、多元宇宙のさらなる一般化の可能性を示した。

Report

(5 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • 2019 Research-status Report
  • 2018 Research-status Report
  • Research Products

    (37 results)

All 2022 2021 2020 2019 2018

All Journal Article (17 results) (of which Peer Reviewed: 12 results,  Open Access: 3 results) Presentation (20 results) (of which Int'l Joint Research: 8 results,  Invited: 7 results)

  • [Journal Article] The coloring number and the list-chromatic number of uncountable graphs2022

    • Author(s)
      Toshimichi Usuba
    • Journal Title

      Israel Journal of Mathematics

      Volume: -

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Equalities for the extent of infinite products and Σ-products2022

    • Author(s)
      Hirata Yasushi、Usuba Toshimichi、Yajima Yukinobu
    • Journal Title

      Topology and its Applications

      Volume: 307 Pages: 107946-107946

    • DOI

      10.1016/j.topol.2021.107946

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] 無限積空間と${Sigma}$-積空間における基数関数extentの等式について2022

    • Author(s)
      平田康史 薄葉季路 矢島幸信
    • Journal Title

      数理解析研究所講究録

      Volume: 2209 Pages: 64-74

    • Related Report
      2021 Annual Research Report
    • Open Access
  • [Journal Article] Geology of symmetric grounds2021

    • Author(s)
      Toshimichi Usuba
    • Journal Title

      Proceedings of the 16th Asian Logic Conference

      Volume: -

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] A note on δ-strongly compact cardinals2020

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Topology and its Applications

      Volume: - Pages: 107538-107538

    • DOI

      10.1016/j.topol.2020.107538

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] On Countable Stationary Towers2020

    • Author(s)
      Yo Matsubara, Toshimichi Usuba
    • Journal Title

      Proceedings of Symposium on Advances in Mathematical Logic 2018

      Volume: -

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Choiceless Lowenheim-Skolem property and uniform definability of grounds2020

    • Author(s)
      Toshimichi Usuba
    • Journal Title

      Proceedings of Symposium on Advances in Mathematical Logic 2018

      Volume: -

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] A note on Lowenheim-Skolem cardinals2020

    • Author(s)
      Toshimichi Usuba
    • Journal Title

      京都大学数理解析研究所講究録

      Volume: -

    • NAID

      120006956550

    • Related Report
      2019 Research-status Report
    • Open Access
  • [Journal Article] A note on the tightness of G-modifications2019

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Topology and its Applications

      Volume: 265 Pages: 106820-106820

    • DOI

      10.1016/j.topol.2019.106820

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Products of Lindeloef spaces with points $G_delta$2019

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Topology and its Applications

      Volume: 252 Pages: 90-96

    • DOI

      10.1016/j.topol.2018.11.019

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] On the existence of skinny stationary subsets2019

    • Author(s)
      Matsubara Yo、Sakai Hiroshi、Usuba Toshimichi
    • Journal Title

      Annals of Pure and Applied Logic

      Volume: 170 Issue: 5 Pages: 539-557

    • DOI

      10.1016/j.apal.2018.12.003

    • NAID

      120006604682

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] $G_\delta $-topology and compact cardinals2019

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Fundamenta Mathematicae

      Volume: 246 Issue: 1 Pages: 71-87

    • DOI

      10.4064/fm487-7-2018

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] Notes on $G_\kappa$-subsets of compact-like spaces,2019

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      京都数理解析研究所講究録

      Volume: 印刷中

    • Related Report
      2018 Research-status Report
  • [Journal Article] New combinatorial principle on singular cardinals and normal ideals2018

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Mathematical Logic Quarterly

      Volume: 64 Issue: 4-5 Pages: 395-408

    • DOI

      10.1002/malq.201700024

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] Extendible cardinals and the mantle2018

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      Archive for Mathematical Logic

      Volume: 58 Issue: 1-2 Pages: 71-75

    • DOI

      10.1007/s00153-018-0625-4

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] On skinny subsets of $P_\kappa \lambda$2018

    • Author(s)
      Matsubara Yo, Sakai Hiroshi, Usuba Toshmichi
    • Journal Title

      京都大学数理解析研究所講究録

      Volume: 2081 Pages: 1-6

    • Related Report
      2018 Research-status Report
  • [Journal Article] Notes on products of Lindel\"of spaces with points $G_\delta$2018

    • Author(s)
      Usuba Toshimichi
    • Journal Title

      京都数理解析研究所講究録

      Volume: 2081 Pages: 57-61

    • Related Report
      2018 Research-status Report
  • [Presentation] Generically extendible cardinals2021

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2021 年度秋季総合分科会
    • Related Report
      2021 Annual Research Report
  • [Presentation] Equalities for the extent of infinite products and Σ-products2021

    • Author(s)
      矢島幸信 平田康史 薄葉季路
    • Organizer
      日本数学会2021 年度秋季総合分科会
    • Related Report
      2021 Annual Research Report
  • [Presentation] Generic setwise large cardinals2021

    • Author(s)
      Toshimichi Usuba
    • Organizer
      Kobe Set Theory Workshop 2021
    • Related Report
      2020 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Variants of strong Chang's conjecture2021

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2021年度年会
    • Related Report
      2020 Research-status Report
  • [Presentation] On Reinhardt cardinals2020

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2020年度秋季総合分科会
    • Related Report
      2020 Research-status Report
  • [Presentation] On generically extendible cardinals2020

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2020 年度年会
    • Related Report
      2019 Research-status Report
  • [Presentation] Choiceless set-theoretic geology2019

    • Author(s)
      Toshimichi Usuba
    • Organizer
      Higher recursion theory and set theory
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Choiceless set-theoretic geology2019

    • Author(s)
      Toshimichi Usuba
    • Organizer
      Asian Logic Conference 2019
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Large cardinals as natural upper bounds on cardinal functions2019

    • Author(s)
      Toshimichi Usuba
    • Organizer
      3rd Pan-Pacific International Conference on Topology and Applications
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] Geology of symmetric grounds2019

    • Author(s)
      Toshimichi Usuba
    • Organizer
      Set Theory and Infinity
    • Related Report
      2019 Research-status Report
    • Int'l Joint Research
  • [Presentation] Standard and choiceless set-theoretic geology2019

    • Author(s)
      薄葉季路
    • Organizer
      Summer School 2019
    • Related Report
      2019 Research-status Report
    • Invited
  • [Presentation] 多元宇宙の理論2019

    • Author(s)
      薄葉季路
    • Organizer
      山陰 基礎論・解析学セミナー 2019
    • Related Report
      2018 Research-status Report
  • [Presentation] GCH at strongly compact cardinals2019

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2019年度年会
    • Related Report
      2018 Research-status Report
  • [Presentation] The generic multiverse and large cardinals2018

    • Author(s)
      Usuba Toshimichi
    • Organizer
      Symposium on Advances in Mathematical Logic 2018
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] $\omega_1$-strongly compact cardinals and cardinal functions in topology2018

    • Author(s)
      Usuba Toshimichi
    • Organizer
      Reflections on Set Theoretic Reflection
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Syntactical and semantical approach to generic multiverse2018

    • Author(s)
      Usuba Toshimichi
    • Organizer
      Sendai Logic School 2018
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] $G_\delta$-topology and compact cardinals2018

    • Author(s)
      薄葉季路
    • Organizer
      一般位相幾何学の進展と諸問題
    • Related Report
      2018 Research-status Report
  • [Presentation] Extendible cardinals and the mantle2018

    • Author(s)
      薄葉季路
    • Organizer
      日本数学会2018年度秋季総合分科会
    • Related Report
      2018 Research-status Report
  • [Presentation] 数学基礎論と位相空間論のコンパクト2018

    • Author(s)
      薄葉季路
    • Organizer
      筑波大学数学域談話会
    • Related Report
      2018 Research-status Report
    • Invited
  • [Presentation] Axiomatization of Generic Multiverse2018

    • Author(s)
      薄葉季路
    • Organizer
      証明論研究集会 2018
    • Related Report
      2018 Research-status Report

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Published: 2018-04-23   Modified: 2023-12-25  

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