In this paper we show theorems concerning automorphisms of models of Peano Arithmetic. These results were obtained by KOTLARSKI [ 2 ] , 5 4 (as K~TLARSKI informed the author, at least part of these results were obtained by ALENA VENCOVSKA (unpublished) and CRAIG SMORYNSKI [4]). KoTLARbKI asked the a
On the structure of kripke models of heyting arithmetic
✍ Scribed by Zoran Marković
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 456 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0044-3050
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Since in Heyting Arithmetic (HA) all atomic formulas are decidable, a Kripke model for HA may be regarded classically as a collection of classical structures for the language of arithmetic, partially ordered by the submodel relation. The obvious question is then: are these classical structures models of Peano Arithmetic (PA)? And dually: if a collection of models of PA, partially ordered by the submodel relation, is regarded as a Kripke model, is it a model of HA? Some partial answers to these questions were obtained in [6], [3], [1] and [2]. Here we present some results in the same direction, announced in [7]. In particular, it is proved that the classical structures at the nodes of a Kripke model of HA must be models of IΔ~1~ (PA^‐^ with induction for provably Δ~1~ formulas) and that the relation between these classical structures must be that of a Δ~1~‐elementary submodel. MSC: 03F30, 03F55.
📜 SIMILAR VOLUMES
PA we define the rfcursively saturated part of XU by RS(9Jl) = ( a E $1: ( 3 8 < YJ?) ( a E )%I and 8 is recursively saturated)). We shall study various possibilities for the relationship between 912 and RS(XU). Tliii paper has grown out of our observation that it may happen that , D is a simple ex
## Abstract Let __M__ be a model of first order Peano arithmetic (**PA**) and __I__ an initial segment of __M__ that is closed under multiplication. Let__M__~0~ be the {0, 1,+}‐reduct of__M__. We show that there is another model __N__ of **PA** that is also an expansion of __M__~0~ such that __a__