## Then-rea enumeration degrees are dense

- Alistair H. Lachlan, Richard A. Shore
- Arch. Math. Log.
- 1992

We show that the 2 enumeration degrees are dense. We also show that for every nonzero n-c. e. e-degree a, with n ≥ 3, one can always find a nonzero 3-c. e. e-degree b such that b < a; on the other hand there is a nonzero ω-c. e. e-degree which bounds no nonzero n-c. e. e-degree. Enumeration reducibility is a formalization of the intuitive notion of relative… (More)

- Recursively enumerable set
- Turing degree
- Existential quantification
- Computable function
- Laboratory information management system
- Mathematics Subject Classification
- Turing
- Approximation
- Computability theory
- Breath of Fire III
- Recursion
- Algorithm
- Characteristic function (convex analysis)
- Universal quantification

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