|
|||||
|
|
Relatively Recursively Enumerable Versus Relatively Σ1 in Models of Peano Arithmetic |
|
| Authors: | Grzegorz Michalski |
| 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: | Recursively enumerable Σ 1 definable Models of Peano Arithmetic Forcing |