@article{fa17c1fbc8dd45189ffd76652cff3ae5,
title = "Relatively Recursively Enumerable vs. Relatively Σ1 in Models Of Peano Arithmetic",
abstract = " We show that that every countable model of PA has a conservative extension M with a subset Y such that a certain Σ1(Y)-formula defines in M a subset which is not r. e. relative to Y.",
keywords = "Forcing, Models of Peano Arithmetic, Recursively enumerable, Σ1 definable",
author = "Michalski, {Grzegorz J.}",
note = "We show that that every countable model of PA has a conservative extension M with a subset Y such that a certain Σ1(Y)‐formula defines in M a subset which is not r. e. relative to Y.",
year = "1995",
doi = "10.1002/malq.19950410408",
language = "American English",
volume = "41",
journal = "Mathematical Logic Quarterly",
issn = "0942-5616",
publisher = "Wiley-VCH Verlag",
}