On the distribution of Lachlan nonsplitting bases
نویسندگان
چکیده
We say that a computably enumerable (c.e.) degree b is a Lachlan nonsplitting base (LNB), if there is a computably enumerable degree a such that a > b, and for any c.e. degrees w,v ≤ a, if a ≤ w ∨ v ∨ b then either a ≤ w ∨ b or a ≤ v ∨ b. In this paper we investigate the relationship between bounding and nonbounding of Lachlan nonsplitting bases and the high /low hierarchy. We prove that there is a non-Low2 c.e. degree which bounds no Lachlan nonsplitting base.
منابع مشابه
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عنوان ژورنال:
- Arch. Math. Log.
دوره 41 شماره
صفحات -
تاریخ انتشار 2002