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THE COMPLEMENTS OF LOWER CONES OF DEGREES AND THE DEGREE SPECTRA OF STRUCTURES

Published online by Cambridge University Press:  15 August 2016

URI ANDREWS
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF WISCONSIN 480 LINCOLN DR. MADISON, WI 53706, USAE-mail: andrews@math.wisc.eduURL: www.math.wisc.edu/∼andrews
MINGZHONG CAI
Affiliation:
DEPARTMENT OF MATHEMATICS DARTMOUTH COLLEGE HANOVER, NH 03755, USAE-mail: mingzhong.cai@dartmouth.eduURL: math.dartmouth.edu/∼cai
ISKANDER SH. KALIMULLIN
Affiliation:
INSTITUTE OF MATHEMATICS AND MECHANICS KAZAN FEDERAL UNIVERSITY KREMLEVSKAYA ST. 18 420008 KAZAN, RUSSIAE-mail: Iskander.Kalimullin@kpfu.ruURL: kpfu.ru/main?p_id=10721
STEFFEN LEMPP
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF WISCONSIN 480 LINCOLN DR. MADISON, WI 53706, USAE-mail: lempp@math.wisc.eduURL: www.math.wisc.edu/∼lempp
JOSEPH S. MILLER
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF WISCONSIN 480 LINCOLN DR. MADISON, WI 53706, USAE-mail: jmiller@math.wisc.eduURL: www.math.wisc.edu/∼jmiller
ANTONIO MONTALBÁN
Affiliation:
DEPARTMENT OF MATHEMATICS UNIVERSITY OF CALIFORNIA-BERKELEY EVANS HALL #3840 BERKELEY, CA 94720, USAE-mail: antonio@math.berkeley.eduURL: www.math.berkeley.edu/∼antonio

Abstract

We study Turing degrees a for which there is a countable structure ${\cal A}$ whose degree spectrum is the collection {x : xa}. In particular, for degrees a from the interval [0′, 0″], such a structure exists if a′ = 0″, and there are no such structures if a″ > 0‴.

Type
Articles
Copyright
Copyright © The Association for Symbolic Logic 2016 

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