Wadge Degrees ofω-Languages of Deterministic Turing Machines
Victor Selivanov · RAIRO - Theoretical Informatics and Applications · 2003
We describe Wadge degrees of ω-languages recognizable by deterministic Turing machines. In particular, it is shown that the ordinal corresponding to these degrees is ξω where ξ = ω1CK is the first non-recursive ordinal known as the Church–Kleene ordinal. This answers a question raised in [2].