The continuity of cupping to \(\text \textbf{0}'\)
type: Item
instance of: scholarly article
title: The continuity of cupping to \(\text \textbf{0}'\)
zbMATH Open document ID: 0805.03030
DOI: 10.1016/0168-0072(93)90143-2
author: Alistair H. Lachlan
author: Robert I. Soare
author: Klaus Ambos-Spies
published in: Annals of Pure and Applied Logic
publication date: 1995-01-29T00:00:00Z
review text: Let \({\mathbf a}\) and \({\mathbf b}\) be recursively enumerable (r.e.) Turing degrees less than \(\mathbf{0}'\) such that \({\mathbf a}\cup {\mathbf b}=\text{\textbf{0}}'\). A degree \({\mathbf c}\) is called a major subdegree of \({\mathbf a}\) if \({\mathbf c}< {\mathbf a}\) and \({\mathbf c}\cup {\mathbf b}= \mathbf{0}'\). It is unknown whether every r.e. degree \({\mathbf a}\) except \(\mathbf{0}\) and \(\mathbf{0}'\) has a major subdegree. In the paper, a group of well-known specialists gives a particular answer to this question.
Mathematics Subject Classification ID: 03D25
zbMATH DE Number: 503600
zbMATH Keywords: Turing degrees
zbMATH Keywords: major subdegree
reviewed by: Sh. T. Ishmukhametov
MaRDI profile type: Publication
full work available at URL: 0168-0072(93)90143-2
OpenAlex ID: W2055640873
cites work: An Algebraic Decomposition of the Recursively Enumerable Degrees and the Coincidence of Several Degree Classes with the Promptly Simple Degrees
cites work: Q4694275
cites work: Q4040892
description: scientific article; zbMATH DE number 503600