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Relatively Recursively Enumerable Versus Relatively Σ1 in Models of Peano Arithmetic

✍ Scribed by Grzegorz Michalski


Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
416 KB
Volume
41
Category
Article
ISSN
0044-3050

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✦ Synopsis


Abstract

We show that that every countable model of PA has a conservative extension M with a subset Y such that a certain Σ~1~(Y)‐formula defines in M a subset which is not r. e. relative to Y.