Shunsuke Yatabe(National Institute of Advanced Industrial Science and Technology)
Specialty: philosophical logic
I am a logician, and I am interested in a logical theories of the
circularity. 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 or the liar paradox in 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. Such form of
the circularity is not only interesting as itself, but also worth
studying, for it is an ideal generalization of a recursion in classical
recursion theory.