On strongly jump traceable reals

Keng Meng Ng
2008 Annals of Pure and Applied Logic  
In this paper we show that there is no minimal bound for jump traceability. In particular, there is no single order function such that strong jump traceability is equivalent to jump traceability for that order. The uniformity of the proof method allows us to adapt the technique to showing that the index set of the c.e. strongly jump traceables is Π 0 4 -complete.
doi:10.1016/j.apal.2007.11.014 fatcat:copmnhys5rcnzj7pdsnsv5w43y