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A note on the Σ1 collection scheme and fragments of bounded arithmetic

✍ Scribed by Zofia Adamowicz; Leszek Aleksander Kołodziejczyk


Publisher
John Wiley and Sons
Year
2010
Tongue
English
Weight
115 KB
Volume
56
Category
Article
ISSN
0044-3050

No coin nor oath required. For personal study only.

✦ Synopsis


Bounded arithmetic, collection principle, weak pigeonhole principle.

MSC (2000) 03F30

We show that for each n ≥ 1, if T n 2 does not prove the weak pigeonhole principle for Σ b n functions, then the collection scheme BΣ1 is not finitely axiomatizable over T n 2 . The same result holds with S n 2 in place of T n 2 .


📜 SIMILAR VOLUMES


A note on effective ultrapowers: Uniform
✍ Thomas McLaughlin 📂 Article 📅 1993 🏛 John Wiley and Sons 🌐 English ⚖ 302 KB

## Abstract By suitably adapting an argument of Hirschfeld (see [2, Chapter 9]), we show that there is a single Δ~1~ formula that defeats “bounded collection” for any model of II~2~ Arithmetic that is either a recursive ultrapower or an existentially complete model. Some related facts are noted. MS