Lemma 14.3.6. If x is image-random and yh x, then there is a recursive ordinal γ such that yT ximage(γ).

Proof. Since x is image-random, we have image = image. Let yh x. Then there is a formula with rank at most β0 < such that

By Lemma 13.1.1, there is a recursive ordinal ...

Get Recursion Theory now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.