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.
| Original language | English |
|---|---|
| Pages (from-to) | 515-522 |
| Number of pages | 8 |
| Journal | Mathematical Logic Quarterly |
| Volume | 41 |
| Issue number | 4 |
| DOIs | |
| State | Published - 1995 |
Scopus Subject Areas
- Logic
Keywords
- Forcing
- Models of Peano Arithmetic
- Recursively enumerable
- Σ definable