横山 啓太

The strength of SCT soundness 

Journal of Logic and Computation 2018年  査読有り

Erdos-Moser and ISigma_2 

2018年

Some upper bounds on ordinal-valued Ramsey numbers for colourings of pairs 

2018年

A parameterized halting problem, the linear time hierarchy, and the MRDP theorem 

Proceedings of the 33rd Annual ACM/IEEE Symposium on Logic in Computer Science 235 - 244 2018年  査読有り

The proof-theoretic strength of Ramsey's theorem for pairs and two colors 

Advances in Mathematics 330 1034 - 1070 2018年  査読有り

A generalization of Levin-Schnorr's theorem 

2013年

Ramsey's theorem and sizes of proofs 

Workshop on Ramsey Theory and Computability 2018年7月   招待有り

Ramsey's theorem in arithmetic 

2018 Winter Meeting of the Association of Symbolic Logic 2018年1月   招待有り

On the first-order part of Ramsey's theorem for pairs 

Computability Theory and Foundations of Mathematics 2017 2017年9月   招待有り

On the first-order strength of Ramsey's theorem in reverse mathematics 

Logic Colloquium 2017 (Special session on computability) 2017年8月   招待有り

Caristi's fixed point theorem in reverse mathematic 

Twelfth International Conference on Computability, Complexity and Randomness (CCR 2017) 2017年7月   招待有り

Second Workshop on Mathematical Logic and its Applications 

Ryota Akiyoshi (Waseda, Japan)Makoto Fujiwara (Waseda, Japan)Tatsuji Kawai (Padova, Italy)Takako Nemoto (JAIST, Japan, chair)Keita Yokoyama (JAIST, Japan) Kanazawa Tokyu Hotel, Ishikawa, Japan 2018年3月5日 - 2018年3月9日

Computability Theory and Foundations of Mathematics 2016 

Makoto Fujiwara (Waseda University, co-chair)Florian Pelupessy (Tohoku University)Kazuyuki Tanaka (Tohoku University, co-chair)Toshimichi Usuba (Waseda University)Keita Yokoyama (JAIST) Waseda University, Tokyo, Japan 2016年9月20日 - 2016年9月21日

Computability Theory and Foundations of Mathematics 2015 

Programme Committee Chi Tat Chong (National University of Singapore, co-chair) Kojiro Higuchi (Chiba University) Makoto Kikuchi (Kobe University) Takako Nemoto (JAIST) Stephen G. Simpson (Pennsylvania State University, co-chair) Toshimic Tokyo Institute of Technology 2015年9月7日 - 2015年9月11日

Computability Theory and Foundations of Mathematics 2014 

Organising CommitteeHajime Ishihara (JAIST)Ryo Kashima (Tokyo Institute of Technology, local chair)Sam Sanders (Ghent)Stephen G. Simpson (Pennsylvania State University)Kazuyuki Tanaka (Tohoku, chair)Keita Yokoyama (JAIST)Programme CommitteeKojiro Higuchi Tokyo Institute of Technology