You are viewing a javascript disabled version of the site. Please enable Javascript for this site to function properly.
Go to headerGo to navigationGo to searchGo to contentsGo to footer
In content section. Select this link to jump to navigation

The Σ2 theory of Dh(⩽hO) as an uppersemilattice with least and greatest element is decidable

Article type: Research Article

Authors: Barnes, James; *

Affiliations: Mathematics Department, Yale University, CT, USA. j.barnes@yale.edu

Correspondence: [*] Corresponding author. j.barnes@yale.edu.

Abstract: The decidability of the two quantifier theory of the hyperarithmetic degrees below Kleene’s O in the language of uppersemilattices with least and greatest element is established. This requires a new kind of initial segment result and a new extension of embeddings result both in the hyperarithmetic setting.

Keywords: Recursion theory, hyperarithmetic theory

DOI: 10.3233/COM-210308

Journal: Computability, vol. 10, no. 4, pp. 305-325, 2021

Published: 7 October 2021
Price: EUR 27.50
Show more