[logic-ml] 東北大ロジックセミナーのご案内(8月29日)

[YOKOYAMA Keita]

皆様

東北大の横山です．
直前のご案内になりまして恐縮ですが，以下の通りセミナーを開催いたしますのでご案内いたします．

https://sites.google.com/view/sendai-logic/

日時：8月29日(火) 15:00-
場所：東北大学理学研究科合同A棟803号室
(当日はzoom配信を実施予定です．
zoomにて参加を希望される方は，五十里さん(hiroyuki.ikari.q8 at dc.tohoku.ac.jp)までご連絡ください)

講演者：仁木哲 (ルール大学ボーフム)

題目：
How can an intuitionistic logician understand connexive constructible falsity?

概要：
Constructivists have usually understood negation as an implication to
absurdity. Nonetheless, there have also been dissenting voices to this
conception, one of the most notable among which are ones who advocate
an alternative notion called constructible falsity. Nels David Nelson
(1918-2003) introduced this notion as a `strong’ form of negation,
which provides a direct counter-example to its negand. This
`strongness’ is however often eschewed in favour of paraconsistency,
making the resulting negation, severed of its relationship with
intuitionistic negation, harder for intuitionistic logicians to
comprehend. The issue is more serious in a variant of constructible
falsity introduced by Heinrich Wansing, which validates so-called
`connexive’ principles. This is due to the provability of a
contradictory pair of formulas, which prohibits an interpretation of
it as a `strong’ negation without bringing triviality. As a result,
Wansingian negation should appear even more mysterious to the eyes of
intuitionistic logicians. Another way to relate intuitionistic and
Wansingian negations is to accept the law of excluded middle for the
latter, as studied by Wansing and Hitoshi Omori. This move, however,
compromises constructivity, and therefore is perhaps not so preferable
either. In this talk, I will try to shed some lights on this issue, by
discussing other ways to introduce an interaction between
intuitionistic and Wansing negations. I will compare relative
advantages of the interactions, which may enable intuitionistic
logicians to better understand Wansingian negation and its
connexivity.


どうぞよろしくお願いいたします．

横山啓太
-- 
Keita Yokoyama
Mathematical Institute, Tohoku University
Aoba, Sendai, JAPAN, 980-8578
keita.yokoyama.c2 at tohoku.ac.jp