Geodesic
Embedding of Countable Orders in Turing Degrees
Matematičeskie zametki, Tome 72 (2002) no. 5, pp. 682-687 
Sh. T. Ishmukhametov. Embedding of Countable Orders in Turing Degrees. Matematičeskie zametki, Tome 72 (2002) no. 5, pp. 682-687. http://geodesic.mathdoc.fr/item/MZM_2002_72_5_a5/
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Voir la notice de l'article provenant de la source Math-Net.Ru

In their classical papers, Lerman, Lachlan, and Lebeuf developed the embedding method, which provides constructions of initial segments of Turing degrees isomorphic to various partially ordered structures. We analyze this method and prove that there is a nonzero degree below each decreasing chain of degrees uniform in $\mathbf 0'$. This imposes restrictions on the application of the embedding method.

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