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» The ibT degrees of computably enumerable sets are not dense
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APAL
2006
123views more  APAL 2006»
13 years 4 months ago
The ibT degrees of computably enumerable sets are not dense
Abstract. We show that the identity bounded Turing degrees of computably enumerable sets are not dense.
George Barmpalias, Andrew E. M. Lewis
APAL
2010
125views more  APAL 2010»
13 years 4 months ago
The computable Lipschitz degrees of computably enumerable sets are not dense
The computable Lipschitz reducibility was introduced by Downey, Hirschfeldt and LaForte under the name of strong weak truthtable reducibility [6]. This reducibility measures both t...
Adam R. Day
APAL
2011
12 years 11 months ago
Upper bounds on ideals in the computably enumerable Turing degrees
We study ideals in the computably enumerable Turing degrees, and their upper bounds. Every proper Σ0 4 ideal in the c.e. Turing degrees has an incomplete upper bound. It follows t...
George Barmpalias, André Nies
CIE
2005
Springer
13 years 10 months ago
Computably Enumerable Sets in the Solovay and the Strong Weak Truth Table Degrees
The strong weak truth table reducibility was suggested by Downey, Hirschfeldt, and LaForte as a measure of relative randomness, alternative to the Solovay reducibility. It also occ...
George Barmpalias
APAL
1998
121views more  APAL 1998»
13 years 4 months ago
Computably Enumerable Sets and Quasi-Reducibility
We consider the computably enumerable sets under the relation of Qreducibility. We first give several results comparing the upper semilattice of c.e. Q-degrees, RQ, ≤Q , under ...
Rodney G. Downey, Geoffrey LaForte, André N...