9 search results - page 1 / 2 » Upper bounds on ideals in the computably enumerable Turing d... |
APAL
2011
12 years 11 months ago
2011
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...
APAL
2006
13 years 4 months ago
2006
Abstract. We show that the identity bounded Turing degrees of computably enumerable sets are not dense.
APAL
2010
13 years 4 months ago
2010
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...
APAL
2011
12 years 11 months ago
2011
The terms of the upper and lower central series of a nilpotent computable group have computably enumerable Turing degree. We show that the Turing degrees of these terms are indepe...
APAL
1998
13 years 4 months ago
1998
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 ...