THE n-r.e. DEGREES: UNDECIDABILITY AND Σ1 SUBSTRUCTURES

被引:3
|
作者
Cai, Mingzhong [1 ]
Shore, Richard A. [2 ]
Slaman, Theodore A. [3 ]
机构
[1] Univ Wisconsin, Dept Math, Madison, WI 53706 USA
[2] Cornell Univ, Dept Math, Ithaca, NY 14853 USA
[3] Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA
基金
美国国家科学基金会;
关键词
Turing degree; n-recursively enumerable; undecidability; Sigma(1)-substructure; DRE DEGREES;
D O I
10.1142/S0219061312500055
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
We study the global properties of D-n, the Turing degrees of the n-r.e. sets. In Theorem 1.5, we show that the first order of D-n is not decidable. In Theorem 1.6, we show that for any two n and m with n < m, D-n is not a Sigma(1)-substructure of D-m.
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页数:30
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