© The Author, 2005. Published by Oxford University Press. All rights reserved.
Original Articles |
A note on Hájek, Paris and Shepherdson's theorem
Department of Computer and System Engineering, Kobe University, Rokko-dai, Nada-ku, Kobe 657-8501, Japan. E-mail: yatabe{at}kurt.scitec.kobe-u.ac.jp
We prove a set-theoretic version of Hájek, Paris and Shepherdson's theorem [HPS00] as follows: The set
of natural numbers must contain a non-standard natural number in any natural Tarskian semantics of C
0(
), the set theory with comprehension principle within Lukasiewicz's infinite-valued predicate logic. The key idea of the proof is a generalization of the derivation of Moh Shaw-Kwei's paradox, which is a Russell-like paradox for many-valued logic.
Key Words:
ukasiewicz's infinite-valued predicate logic, set theory, the comprehension principle, truth predicate, non-standard natural number
Received 9 September 2004. Revised 11 November 2004.