论文信息 - On extensions of models of strong fragments of arithmetic

On extensions of models of strong fragments of arithmetic

Using a weak notion of recursive saturation (not always semiregularity) we prove that there are no finitely generated countable models of BXn + -'IXn(n > 0) . We consider the problem of not almost semiregularity of models of IX,n + --BXn+l . From a partial solution to this problem we deduce a generalization of the theorem of Smorynski and Stavi on cofinal extensions of recursively saturated models of arithmetic.

Roman Kossak

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