@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",

}