Structural Properties and $\Sigma^0_2$ Enumeration Degrees
Nies, Andre ; Sorbi, Andrea
J. Symbolic Logic, Tome 65 (2000) no. 1, p. 285-292 / Harvested from Project Euclid
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We prove that each $\Sigma^0_2$ set which is hypersimple relative to $\emptyset$' is noncuppable in the structure of the $\Sigma^0_2$ enumeration degrees. This gives a connection between properties of $\Sigma^0_2$ sets under inclusion and and the $\Sigma^0_2$ enumeration degrees. We also prove that some low non-computably enumerable enumeration degree contains no set which is simple relative to $\emptyset$'.
Publié le : 2000-03-14
Classification:  
@article{1183746021,
     author = {Nies, Andre and Sorbi, Andrea},
     title = {Structural Properties and $\Sigma^0\_2$ Enumeration Degrees},
     journal = {J. Symbolic Logic},
     volume = {65},
     number = {1},
     year = {2000},
     pages = { 285-292},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183746021}
}

Nies, Andre; Sorbi, Andrea. Structural Properties and $\Sigma^0_2$ Enumeration Degrees. J. Symbolic Logic, Tome 65 (2000) no. 1, pp.  285-292. http://gdmltest.u-ga.fr/item/1183746021/