English

COH, SRT22, and multiple functionals

Logic 2020-07-03 v3

Abstract

We prove the following result: there is a family R=R0,R1,R = \langle R_0,R_1,\ldots \rangle of subsets of ω\omega such that for every stable coloring c:[ω]2kc : [\omega]^2 \to k hyperarithmetical in RR and every finite collection of Turing functionals, there is an infinite homogeneous set HH for cc such that none of the finitely many functionals map RHR \oplus H to an infinite cohesive set for RR. This extends the current best partial results towards the SRT22\mathsf{SRT}^2_2 vs. COH\mathsf{COH} problem in reverse mathematics, and is also a partial result towards the resolution of several related problems, such as whether COH\mathsf{COH} is omnisciently computably reducible to SRT22\mathsf{SRT}^2_2.

Keywords

Cite

@article{arxiv.1905.00321,
  title  = {COH, SRT22, and multiple functionals},
  author = {Damir Dzhafarov and Ludovic Patey},
  journal= {arXiv preprint arXiv:1905.00321},
  year   = {2020}
}

Comments

13 pages

R2 v1 2026-06-23T08:54:19.329Z