Enumerations, Countable Structures and Turing Degrees
نویسنده
چکیده
It is proven that there is a family of sets of natural numbers which has enumerations in every Turing degree except for the recursive degree. This implies that there is a countable structure which has representations in all but the recursive degree. Moreover, it is shown that there is such a structure which has a recursively represented elementary extension.
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تاریخ انتشار 1998