The Journal of Symbolic Logic

Research Article

RT2 2 does not imply WKL0

Jiayi Liu

Department of Mathematics, Central South University, South Campus, South Dormitory No. 6 Room 619, Changsha, 410083, China, E-mail:


We prove that by showing that for any set C not of PA-degree and any set A, there exists an infinite subset G of A or such that GC is also not of PA-degree.

(Received October 26 2010)

Key words and phrases

  • recursion theory;
  • computability theory;
  • reverse mathematics;
  • Ramsey's theorem;
  • weak Konig lemma;
  • Mathias forcing