Lattice initial segments of the Turing degrees

Bjørn Kjos-Hanssen

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arXiv · 0901.3876

Lattice initial segments of the Turing degrees

Bjørn Kjos-Hanssen

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Abstract

We characterize the isomorphism types of principal ideals of the Turing degrees below 0' that are lattices as the lattices with a Sigma-0-3 presentation, by showing that each Sigma-0-3 presentable bounded upper semilattice is isomorphic to such a principal ideal. We get a similar result for the Turing degrees below any degree above 0".

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BibTeX RIS

Bjørn Kjos-Hanssen. 2011-07-13. Lattice initial segments of the Turing degrees. https://arxiv.org/abs/0901.3876

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