| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6425961 | Advances in Mathematics | 2012 | 18 Pages |
Abstract
We study combinatorial principles weaker than Ramsey's theorem for pairs over the RCA0 (recursive comprehension axiom) system with Σ20-bounding. It is shown that the cohesiveness (COH), ascending and descending sequence (ADS), and chain/antichain (CAC) principles are all Π11-conservative over Σ20-bounding. In particular, none of these principles proves Σ20-induction.
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Physical Sciences and Engineering
Mathematics
Mathematics (General)
Authors
C.T. Chong, Theodore A. Slaman, Yue Yang,