Details of the Researcher

PHOTO

Masanobu Toyooka
Section
Graduate School of Information Sciences
Job title
Degree

  • Bachelor in the field of Humanities (Hokkaido University)

  • Master in the field of Humanities (Hokkaido University)

  • Doctor of Philosophy in the field of Humanities (Hokkaido University)

e-Rad No.
71032786

Research History 14

  • 2026/03 - Present
    University of St Andrews　Arché: Philosophical Research Centre for Logic, Language, Metaphysics, and Epistemology　Postdoctoral Visiting Scholar

  • 2025/04 - Present
    Japan Society for the Promotion of Science　Postdoctoral Research Fellow (PD)

  • 2025/04 - Present
    Tohoku University　Graduate School of Information Sciences　Specially Appointed Research Fellow

  • 2025/11 - 2025/11
    University of St Andrews　Arché: Philosophical Research Centre for Logic, Language, Metaphysics, and Epistemology　Postdoctoral Visiting Scholar

  • 2024/10 - 2025/03
    Hokkaido University　School of Humanities and Human Sciences　Part-time Lecturer

  • 2024/07 - 2025/03
    Japan Society for the Promotion of Science　Postdoctoral Research Fellow (PD)

  • 2024/04 - 2024/09
    Hokkaido Musashi Women's Junior College　Part-time Lecturer

  • 2022/04 - 2024/06
    Japan Society for the Promotion of Science　Doctoral Research Fellow (DC1)

  • 2023/04 - 2023/09
    Hokkaido University of Education　Faculty of Education Sapporo Campus　Part-time Lecturer

  • 2023/03 - 2023/03
    Sapporo Mini-workshop on Non-classical logic　Organizer

  • 2023/02 - 2023/02
    Chiba Institute of Technology　Software Technology and Artificial Intelligence Research Laboratory　Research Collaborator (Outside)

  • 2022/04 - 2022/09
    Hokkaido University of Education　Faculty of Education Sapporo Campus　Part-time Lecturer

  • 2020/04 - 2022/09
    Hokkaido University　School of Humanities and Human Sciences　Teaching Assistant

  • 2021/04 - 2021/09
    Hokkaido University　General Education　Teaching Assistant

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Education 3

  • Hokkaido University　Graduate School of Humanities and Human Sciences

    2022/04 - 2024/06

  • Hokkaido University　Graduate School of Humanities and Human Sciences

    2020/04 - 2022/03

  • Hokkaido University　Faculty of Letters

    2016/04 - 2020/03

Professional Memberships 2

  • Japan Association for Philosophy of Science

    2023/06 - Present

  • Philosophy of Science Society, Japan

    2021/01 - Present

Research Interests 12

  • Logical Pluralism

  • Neighborhood Semantics

  • Kripke Semantics

  • Concepts of Negation

  • Sequent Calculus and its Extensions

  • Subintuitionistic Logic

  • Super Intuitionistic Logic

  • Strict implication logic

  • Intuitionistic logic

  • Combined systems of different logics

  • Inferentialism

  • Proof-theoretic semantics

Research Areas 1

  • Humanities & social sciences / Philosophy and ethics / Philosophical Logic

Papers 9

  1. Cut-free Sequent Calculi for Wansing’s Expansions of Nelson’s Logics Peer-reviewed

    Katsuhiko Sano, Masanobu Toyooka

    Studia Logica　2025/11/24

    DOI： 10.1007/s11225-025-10210-z 　

  2. How can we avoid Popper's collapsing problem and have Craig interpolation?

    Masanobu Toyooka, Katsuhiko Sano

    Annals of the Japan Association for Philosophy of Science　33　145-162　2024/12

  3. Combining Intuitionistic and Classical Propositional Logic: Gentzenization and Craig Interpolation Peer-reviewed

    Masanobu Toyooka, Katsuhiko Sano

    Studia Logica　112　1091-1121　2024/10

    DOI： 10.1007/s11225-023-10067-0 　

    ISSN： 0039-3215 1572-8730

  4. An Investigation Into Addition of Classical Negation to First-Order and Generalized Intuitionistic Logic

    Masanobu Toyooka

    Doctoral Dissertation, Graduate School of Humanities and Human Sciences, Hokkaido University　2024/06/30

  5. Semantic incompleteness of del Cerro and Herzig's Hilbert system for a combination of classical and intuitionistic propositional logic International-journal Peer-reviewed

    Masanobu Toyooka, Katsuhiko Sano

    Australasian Journal of Logic　20　(3)　396-410　2023

    Publisher: Victoria University of Wellington Library

    DOI： 10.26686/ajl.v20i3.7696 　

    eISSN： 1448-5052

    More details Close

    This paper shows Hilbert system (C+J)-, given by del Cerro and Herzig (1996) is semantically incomplete. This system is proposed as a proof theory for Kripke semantics for a combination of intuitionistic and classical propositional logic, which is obtained by adding the natural semantic clause of classical implication into intuitionistic Kripke semantics. Although Hilbert system (C+J)- contains intuitionistic modus ponens as a rule, it does not contain classical modus ponens. This paper gives an argument ensuring that the system (C+J)- is semantically incomplete because of the absence of classical modus ponens. Our method is based on the logic of paradox, which is a paraconsistent logic proposed by Priest (1979).

  6. A Proof-Theoretic Analysis of the Meaning of a Formula in a Combination of Intuitionistic and Classical Propositional Logic International-journal Peer-reviewed

    Masanobu Toyooka

    19th International Conference, LENLS19, Tokyo, Japan, November 19–21, 2022, Revised Selected Papers　100-119　2023

    DOI： 10.1007/978-3-031-43977-3_7 　

    ISSN： 0302-9743 1611-3349

  7. Combining first-order classical and intuitionistic logic International-journal Peer-reviewed

    Masanobu Toyooka, Katsuhiko Sano

    Electronic Proceedings in Theoretical Computer Science　358　25-40　2022/04

    DOI： 10.4204/EPTCS.358.3 　

  8. A Peaceful Coexistence of Different Logics and the Concept of Harmony in Proof-Theoretic Semantics (in Japanese) Peer-reviewed

    Masanobu Toyooka

    Japanese Student Research Notes of Philosophy of Science　4　69-77　2021/06

  9. A Connection Between Atomic Base and Completeness in Proof-Theoretic Semantics (Survey Article, in Japanese) Peer-reviewed

    Masanobu Toyooka

    PHS Studies　15　85-111　2021/04

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Misc. 1

  1. Semantic incompleteness of Hilbert system for a combination of classical and intuitionistic logic

    Masanobu Toyooka, Katsuhiko Sano

    arXiv　abs/2207.07416　2022/07

    DOI： 10.48550/ARXIV.2207.07416 　

Presentations 40

  1. Three Benchmarks for Exclusion of Non-Normal Valuations International-presentation

    Masanobu Toyooka

    LOGICA 2026　2026/05/20

  2. Combination of Two Negations and Uniqueness Invited

    Masanobu Toyooka

    The 6th France-Japan Workshop on "Disagreement in Logic and Reasoning and Beyond"　2026/02/28

  3. Three Benchmarks for Classical Connectives

    Masanobu Toyooka

    LLAL＠GSIS (XI)　2026/01/30

  4. On Okada's constructive weak implication

    Masanobu Toyooka

    LLAL＠GSIS (XII)　2026/01/24

  5. Categoricity and expressibility of classical connectives Invited

    Masanobu Toyooka

    PTS Seminar　2025/12/09

  6. On interpretation of constructive implication that avoids circularity

    Masanobu Toyooka

    58th Annual Meeting of Philosophy of Science Society, Japan　2025/11/30

  7. Generalizing subintuitionistic logics over neighborhood semantics

    Masanobu Toyooka

    LLAL＠GSIS (IX)　2025/10/28

  8. Strong completeness of constant domain expansion of Restall's subintuitionistic logic International-presentation

    Masanobu Toyooka, Katsuhiko Sano

    The 6th Taiwan Philosophical Logic Colloquium (TPLC-VI)　2025/10/25

  9. Sequent calculi and Craig interpolation for Došen's logics with negative modality.

    Masanobu Toyooka

    TF Colloquium　2025/10/08

  10. How can we add classical negation to intuitionistic sequent calculus?

    Masanobu Toyooka

    LLAMA Seminar at ILLC　2025/10/07

  11. Craig interpolation for logics of negative modality via cut-free sequent calculus International-presentation

    Masanobu Toyooka, Katsuhiko Sano

    15th Tbilisi Symposium on Logic, Language and Computation (TbiLLC 2025)　2025/09/09

  12. A solution to collapsing problem and an inferentialist approach to intuitionistic and classical connectives

    Masanobu Toyooka

    LLAL＠GSIS (VII)　2025/07/05

  13. Augmented intuitionistic logic for non-monotonic reasoning International-presentation Invited

    Masanobu Toyooka

    APPSA-LMPST Taiwan 2025　2025/06/19

  14. 12 expressibility of logical connectives Invited

    Masanobu Toyooka

    LLAL＠GSIS (VI)　2025/03/04

  15. Humberstone's logic as an extension of minimal logic Invited

    Masanobu Toyooka

    A Kyoto-Taipei Workshop on Logic of Agent　2025/03/02

  16. Gentzenization of Wansing's expansions of Nelson's logics Invited

    Masanobu Toyooka

    LLAL＠GSIS (V)　2025/02/24

  17. How should intuitionists' understanding of classical logic be codified?

    Masanobu Toyooka

    The 4th France-Japan Colloquium ``Disagreement in Logic and Reasoning'' with a Special Panel Session on Normativity and Divergences of Forms of Life　2025/02/21

  18. Humberstone's Ω in Curry's logic D International-presentation

    Masanobu Toyooka

    The Inaugural Symposium on Logic in the Arab World　2025/02/19

  19. Twelve benchmarks of moderate inferentialism for logical connectives Invited

    Masanobu Toyooka

    Hitotsubashi University Seminar in Philosophy and Social Thought　2025/01/25

  20. Star semantics for empirical negation International-presentation

    Masanobu Toyooka

    The Australasian Association for Logic Conference 2024　2024/11/27

  21. Routley star for empirical negation Invited

    Masanobu Toyooka

    LLAL＠GSIS (IV)　2024/09/21

  22. How can empirical negation be understood from the negation as incompatibility on intuitionistic propositional logic?

    Masanobu Toyooka

    Second Hokkaido University-Hitotsubashi University Joint Seminar on Philosophy and Ethics　2024/08/08

  23. Two approaches of adding classical negation to intuitionistic logic

    Masanobu Toyooka

    French-Japan Colloquium: Disagreement in Logic and Reasoning　2024/03/25

  24. Cut-free sequent calculus for Wansing's expansion of Nelson's logic International-presentation

    Katsuhiko Sano, Masanobu Toyooka

    AWPL2024: 6th Asian Workshop on Philosophical Logic　2024/03/05

  25. Neighborhood semantics for weak subintuitionistic logics with the base state

    Masanobu Toyooka

    56th Annual Meeting of Philosophy of Science Society, Japan　2023/12/03

  26. Generalizing Restall’s subintuitionistic logics over neighborhood semantics International-presentation

    Masanobu Toyooka

    The Australasian Association for Logic Conference 2023　2023/11/10

  27. An inferentialist analysis of the concept of truth in the combination of intuitionistic and classical propositional logic C+J

    Masanobu Toyooka

    First Hokkaido University-Hitotsubashi University Joint Seminar on Philosophy and Ethics　2023/09/02

  28. The relationship between Humberstone's logical constant Ω and a Kripke frame for intuitionistic logic

    Masanobu Toyooka, Katsuhiko Sano

    SLACS 2023　2023/08/31

  29. About coexistence of intuitionistic implication and classical negation in the level of first-order logic

    Masanobu Toyooka

    Sapporo Mini-workshop on Non-classical Logic　2023/03/24

  30. Coexistence of different logics focusing on the concepts of negations (short project report)

    Masanobu Toyooka

    France-Japan Workshop on ``Philosophy and Ethics of TV Drama Series'' and ``Disagreement in Logic and Reasoning''　2023/03/16

  31. A collapsing problem of combining intuitionistic and classical logic and a way of avoiding the problem in sequent calculus Invited

    Masanobu Toyooka, Katsuhiko Sano

    Workshop on the Occasion of the UNESCO World Logic Day　2023/01/14

  32. Proof-theoretic analysis of the meaning of a formula in a combined logic C+J of intuitionistic and classical propositional logic

    55th Annual Meeting of Philosophy of Science Society, Japan　2022/12/03

  33. Adding empirical negation into intermediate predicate logic CD Invited

    Masanobu Toyooka

    A Workshop on Empirical Negation　2022/11/26

  34. A proof-theoretic analysis of meaning of a formula in a combination of intuitionistic and classical propositional logic International-presentation

    Masanobu Toyooka

    Logic and Engineering of Natural Language Semantics 19 (LENLS19)　2022/11/20

  35. A tree-sequent method for intermediate predicate logic CD expanded with empirical negation International-presentation

    Masanobu Toyooka

    4th Workshop on Proof Theory and Its Applications　2022/11/12

  36. Addition of empirical negation to intermediate predicate logic CD

    Masanobu Toyooka

    Ōokayama Logic Seminar Summer Intensive Seminar　2022/09/06

  37. Combining first-order classical and intuitionistic logic International-presentation

    Masanobu Toyooka, Katsuhiko Sano

    NCL'22: Non-Classical Logics. Theory and Applications 2022　2022/03/18

  38. Craig interpolation for a sequent calculus for combining intuitionistic and classical propositional logic International-presentation

    Masanobu Toyooka, Katsuhiko Sano

    SOCREAL 2022: 6th International Workshop on Philosophy and Logic of Social Reality　2022/03/01

  39. Proof-theoretic research on a system FOC+J that combines intuitionistic and classical logic

    Masanobu Toyooka

    Ōokayama Logic Seminar　2022/02/21

  40. Analytic multi-succedent sequent calculus for combining intuitionistic and classical propositional logic International-presentation

    Masanobu Toyooka, Katsuhiko Sano

    ICLA 2021: 9th Indian Conference on Logic and its Applications　2021/03/05

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Research Projects 4

  1. A proof-theoretic study of identity of logical constants

    Offer Organization: Japan Society for the Promotion of Science

    System: Grant-in-Aid for Early-Career Scientists

    Institution: Graduate School of Information Sciences, Tohoku University

    2026/04 - 2029/03

  2. A proof-theoretic study of syntactic expansions of intuitionistic logic dealing with empirical statements Competitive

    Offer Organization: Japan Society for the Promotion of Science

    System: Grant-in-Aid for JSPS Fellows

    Institution: Graduate School of Information Sciences, Tohoku University

    2025/04 - 2028/03

  3. Study of intuitionistic implication with respect to philosophy, mathematics, and computer science

    Offer Organization: Graduate School of Information Sciences, Tohoku University

    System: Support for Interdisciplinary Research Projects

    Institution: Graduate School of Information Sciences, Tohoku University

    2025/07 - 2026/03

  4. Proof-Theoretic Research of Coexistence of Different Logics Focusing on the Concepts of Negations Competitive

    Offer Organization: Japan Society for the Promotion of Science

    System: Grant-in-Aid for JSPS Fellows

    Institution: Graduate School / Faculty of Humanities and Human Sciences, Hokkaido University

    2022/04 - 2025/03

Teaching Experience 4

  1. Philosophy　Hokkaido University

  2. Logic　Hokkaido Musashi Women's Junior College

  3. Introduction to Information and Communication Technology　Hokkaido University of Education

  4. Introduction to Information and Communication Technology　Hokkaido University of Education

Academic Activities 3

  1. LLAL (XII), Organizer

    Sendai

    2026/01/23 - 2026/01/24

    Activity type: Academic society, research group, etc.

  2. Week of Logic, Organizer

    Sendai

    2025/11/24 - 2025/11/28

    Activity type: Academic society, research group, etc.

  3. 6th Asian Workshop on Philosophical Logic (AWPL 2024), Local organizing committee

    Sapporo

    2024/03/04 - 2024/03/06

    Activity type: Academic society, research group, etc.

Other 13

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  3. 独立行政法人日本学術振興会 採用最終年次における研究奨励金特別手当

  4. 独立行政法人日本学術振興会 海外特別研究員 採用内定（辞退）

  5. 2023年度前期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）1/2免除

  6. 2022年度後期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）全額免除

  7. 2022年度前期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）1/2免除

  8. 日本学生支援機構 特に優れた業績による第一種奨学金返還免除 半額免除

  9. 2021年度後期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）全額免除

  10. 2021年度前期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）1/2免除

  11. 2020年度後期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）全額免除

  12. 2020年度前期北海道大学大学院「授業料減免」（成績優秀者に家計状況に応じて決定）1/2免除

  13. TOEIC L&R 940点

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