Shunsuke Yatabe

J-GLOBAL         Last updated: Apr 22, 2015 at 12:18
Shunsuke Yatabe
West Japan Railway Company
R&D section
Dr. (Sci)
Other affiliation
Kyoto University


I am a logician, and I am interested in logical theories of the circular phenomenon. So I am studying set theories and truth theories within non-classical logics.
The study of logical theories of the circularity is important not only in logic but also in computer science. For, one of the key concepts, the recursion, has a circular nature since we should calculate the value of 2+1 in order to calculate the value of 2+2. However, it is well-known that the full form of the circularity implies a contradiction, e.g. Russell paradox, the comprehension principle which guarantees the existence of term {x : P(x)} for any formula P(x) implies a contradiction, or the liar paradox in truth theories with full T-scheme in classical logic. Therefore we have to restrict the form of the recursion to have a consistent theory if we keep classical logic.
It is well-known that both the comprehension principle and the full T-scheme do not imply a contradiction in many non-classical logics. These theories allow a very strong form of the circularity, namely a general form of the recursive definition in set theories in substructural logics, and co-inductive definitions in fuzzy truth theories. Such form of the circularity is not only interesting as itself, but also worth studying, for it is an ideal generalization of recursion in classical recursion theory.

Research Areas


Academic & Professional Experience

Apr 2014
Research fellow, Center for Applied Philosophy & Ethics, Graduate School of Letters, Kyoto University
Apr 2013
R&D department, West Japan Railway Company
Apr 2012
Mar 2013
Research scientist (2), System Life-cycle group, Research institute for secure systems, AIST
Apr 2009
part-time Lecturer, Faculty of letters, Kyoto University
Apr 2010
Mar 2012
Research scientist (2), Collaborate Research Team for Verification, AIST

Published Papers

Shunsuke Yatabe
Philosophy and History of Science Studies   (9)    Apr 2015   [Refereed]
Truth theories like the Friedman-Sheard’s truth theory (FS) have two rules, T-in rule and T-out rule, about introduction and elimination of the truth predicate. They look like the introduction rule and the elimination rule of a logical connective....
Shunsuke Yatabe
Logic Journal of IGPL      Nov 2013   [Refereed]
We show that the crispness of ω is not provable in a constructive naive set theory CONS in FLew ∀, intuitionistic predicate logic minus the contraction rule. In the proof, we construct a circularly defined object fix, a fixed point of the successo...
MORI Takashi , Shunsuke YATABE, Hiroyuki YAMAMOTO, Takahiro ARAKAWA, Kenji TAGUCHI, Daisuke SOUMA, Izumi TAKEUTI, Sumitaka AKIBA and Hitoshi OHSAKI
Proceedings of WCRR      Oct 2013   [Refereed]
Shunsuke Yatabe
Philosophy and History of Science   7(1) 1-26   Feb 2013   [Refereed]
Recently some constructivists try to justify impredicative theories with coinduction which play a very significant role in computer science though it had been thought that predicativity is necessary for constructivity. In this paper we introduce t...
Shunsuke Yatabe
New Frontiers in Artificial Intelligence, Lecture Notes in Computer Science   7856 109-124   Jan 2013   [Refereed]
We generalize the framework of Barwise and Etchmendy’s “the liar” to that of coinductive language, and focus on two problems, the mutual identity of Yablo propositions coded by hypersets in ZFA and the difficulty of constructing semantics. We defi...


Shunsuke Yatabe
The procedings of LENLS 9      Dec 2012   [Refereed]
We generalize the framework of Barwise and Etchmendy's ``the liar" to that of coinductive language, and focus on two problems, the mutual identity of Yablo propositions coded by hypersets in ZFA and the difficulty of constructing semantics.
We def...
Yablo's paradox and Tex-inconsistency
Shunsuke Yatabe
The proceeding of Numbers and Truth      Oct 2012   [Refereed]
A constructive naive set theory and the Tex-rule
Shunsuke Yatabe
The proceeding of Logic, algebra and truth degrees 2012      Sep 2012   [Refereed]
Takashi Mori, Shunsuke Yatabe
JREA   55(8) 32-35   Aug 2012
On the crispness of Tex and an arithmetic with a bi-simulation in a constructive naive set theory
Shunsuke Yatabe
The proceeding of Non-classical Modal and Predicate Logics 2012      Dec 2011   [Refereed]

Conference Activities & Talks

Shunsuke Yatabe
Theorem proving and provers for reliable theory and implementations (TPP2014)   5 Dec 2014   
Truth, omega-inconsistency and Harmony
Shunsuke Yatabe
The 2nd Conference on Contemporary Philosophy in East Asia (CCPEA)   28 Aug 2014   
Shunsuke Yatabe
Tokyo Forum of Analytic Philosophy   13 Jun 2014   
Truth theory and harmony
Shunsuke Yatabe
11 May 2014   
Shunsuke Yatabe
11th Workshop of Critical Software System(11thWOCS2 )   15 Jan 2014   

Teaching Experience

  • logic (Faculity of letetrs, Kyoto University)