A note on Bar Induction in Constructive Set Theory
โ Scribed by Michael Rathjen
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 113 KB
- Volume
- 52
- Category
- Article
- ISSN
- 0044-3050
No coin nor oath required. For personal study only.
โฆ Synopsis
Abstract
Bar Induction occupies a central place in Brouwerian mathematics. This note is concerned with the strength of Bar Induction on the basis of Constructive ZermeloโFraenkel Set Theory, CZF. It is shown that CZF augmented by decidable Bar Induction proves the 1โconsistency of CZF. This answers a question of P. Aczel who used Bar Induction to give a proof of the Lusin Separation Theorem in the constructive set theory CZF. (ยฉ 2006 WILEYโVCH Verlag GmbH & Co. KGaA, Weinheim)
๐ SIMILAR VOLUMES
## Abstract Let __M__ be an arbitrary structure. Then we say that an __M__ โformula __ฯ__ (__x__) __defines a stable set in__ __M__ if every formula __ฯ__ (__x__) โง __ฮฑ__ (__x__, __y__) is stable. We prove: If __G__ is an __M__ โdefinable group and every definable stable subset of __G__ has __U__ โ
## Abstract We investigate stationarity of types over models in simple theories. In particular, we show that in simple theories with finite SUโrank, any complete type over a model having CantorโBendixson rank is stationary. (ยฉ 2008 WILEYโVCH Verlag GmbH & Co. KGaA, Weinheim)