A Delta(0)(2) set with no infinite low subset in either it or its complement

Authors
Downey, R Hirschfeldt, DR Lempp, S Solomon, R
Citation
R. Downey et al., A Delta(0)(2) set with no infinite low subset in either it or its complement, J SYMB LOG, 66(3), 2001, pp. 1371-1381
Citations number
2
Categorie Soggetti
Mathematics
Journal title
JOURNAL OF SYMBOLIC LOGIC
ISSN journal
00224812 → ACNP
Volume
66
Issue
3
Year of publication
2001
Pages
1371 - 1381
Database
ISI
SICI code
0022-4812(200109)66:3<1371:ADSWNI>2.0.ZU;2-Q
Abstract
We construct the set of the title, answering a question of Cholak, Jockusch , and Slaman [1], and discuss its connections with the study of the proof-t heoretic strength and effective content of versions of Ramsey's Theorem. In particular, our result implies that every omega -model of RCA(0) + SRT22 m ust contain a nonlow set.