EXTENSIONS OF EMBEDDINGS BELOW COMPUTABLY ENUMERABLE DEGREES

作者：Downey Rod^*; Greenberg Noam; Lewis Andrew; Montalban Antonio

来源：Transactions of the American Mathematical Society, 2013, 365(6): 2977-3018.

• Turing degrees
• decidability
• extensions of embeddings

Toward establishing the decidability of the two-quantifier theory of the Delta(0)(2) Turing degrees with join, we study extensions of embeddings of upper-semi-lattices into the initial segments of Turing degrees determined by computably enumerable sets, in particular, the degree of the halting set 0%26apos;. We obtain a good deal of sufficient and necessary conditions.

• 出版日期2013-6