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Some theorems on R-maximal sets and major subsets of recursively enumerable sets

Published online by Cambridge University Press:  12 March 2014

Manuel Lerman*
Affiliation:
Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

Extract

In [5], we studied the relational systems /Ā obtained from the recursive functions of one variable by identifying two such functions if they are equal for all but finitely many хĀ, where Ā is an r-cohesive set. The relational systems /Ā with addition and multiplication defined pointwise on them, were once thought to be potential candidates for nonstandard models of arithmetic. This, however, turned out not to be the case, as was shown by Feferman, Scott, and Tennenbaum [1]. We showed, letting A and B be r-maximal sets, and letting denote the complement of X, that /Ā and are elementarily equivalent (/Ā) if there are r-maximal supersets C and D of A and B respectively such that C and D have the same many-one degree (C =mD). In fact, if A and B are maximal sets, /Ā if, and only if, A =mB. We wish to study the relationship between the elementary equivalence of /Ā and , and the Turing degrees of A and B.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1971

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References

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