Minimal covers and arithmetical sets
نویسندگان
چکیده
منابع مشابه
Minimal Covers and Arithmetical Sets1
If a and b are degrees of unsolvability, a is called a minimal cover of b if b<a and no degree c satisfies b<c<a. The degree a is called a minimal cover if it is a minimal cover of some degree b. We prove by a very simple argument that 0" is not a minimal cover for any n. From this result and the axiom of Borel determinateness (BD) we show that the degrees of arithmetical sets (with their usual...
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ژورنال
عنوان ژورنال: Proceedings of the American Mathematical Society
سال: 1970
ISSN: 0002-9939
DOI: 10.1090/s0002-9939-1970-0265154-x