Abstract. We prove that for every Σ02 enumeration degree b there exists a noncuppable Σ02 degree a> 0e such that b ′ ≤e a ′ and a′′≤e b′′. This allows us to deduce, from results on the high/low jump hierarchy in the local Turing degrees and the jump preserving properties of the standard embedding ι: DT → De, that there exist Σ02 noncuppable enumeration degrees at every possible—i.e. above low1—level of the high/low jump hierarchy in the context of De. 1
This paper continues the project, initiated in [ACK], of describing general conditions under which r...
This paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], of descri...
We prove the following three theorems on the enumeration degrees of # 0 2 sets. Theorem A: There exi...
Using properties of κ-pairs of sets, we show that every nonzero enumeration degree a bounds a nontr...
We show that there exist downwards properly \Sigma^0_2 (in fact noncuppable) e-degrees that are not...
In this paper we prove the following theorem: For every notation of a constructive ordinal there exi...
AbstractIt is shown that Th(H1)≠Th(Hn) holds for every n>1, where Hm is the upper semi-lattice of al...
this paper. Clearly the most remarkable result relating the jump operator to the ordering of degrees...
The natural embedding of the Turing degrees into the enumeration degrees preserves the jump operatio...
Abstract. A set A is symmetric enumeration (se-) reducible to a set B (A≤seB) if A is enumeration re...
We prove the existence of noncomputable low computably enumerable degrees b < a such that b is stron...
In this paper we investigate questions about the definability of classes of n-computably enumerable ...
AbstractWe prove the following three theorems on the enumeration degrees of ∑20 sets. Theorem A: The...
Abstract. We show that if A and B form a nontrivial K-pair, then there is a semi-computable set C su...
AbstractThis paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], o...
This paper continues the project, initiated in [ACK], of describing general conditions under which r...
This paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], of descri...
We prove the following three theorems on the enumeration degrees of # 0 2 sets. Theorem A: There exi...
Using properties of κ-pairs of sets, we show that every nonzero enumeration degree a bounds a nontr...
We show that there exist downwards properly \Sigma^0_2 (in fact noncuppable) e-degrees that are not...
In this paper we prove the following theorem: For every notation of a constructive ordinal there exi...
AbstractIt is shown that Th(H1)≠Th(Hn) holds for every n>1, where Hm is the upper semi-lattice of al...
this paper. Clearly the most remarkable result relating the jump operator to the ordering of degrees...
The natural embedding of the Turing degrees into the enumeration degrees preserves the jump operatio...
Abstract. A set A is symmetric enumeration (se-) reducible to a set B (A≤seB) if A is enumeration re...
We prove the existence of noncomputable low computably enumerable degrees b < a such that b is stron...
In this paper we investigate questions about the definability of classes of n-computably enumerable ...
AbstractWe prove the following three theorems on the enumeration degrees of ∑20 sets. Theorem A: The...
Abstract. We show that if A and B form a nontrivial K-pair, then there is a semi-computable set C su...
AbstractThis paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], o...
This paper continues the project, initiated in [ACK], of describing general conditions under which r...
This paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], of descri...
We prove the following three theorems on the enumeration degrees of # 0 2 sets. Theorem A: There exi...