Abstract
For any countable nonstandard modelM of a sufficiently strong fragment of arithmeticT, and any nonstandard numbersa, c εM, M⊨c≦a, there is a modelK ofT which agrees withM up toa and such that inK there is a proof of contradiction inT with Gödel number\( \leqq 2^{a^c } \).
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Krajíček, J., Pudlák, P. On the structure of initial segments of models of arithmetic. Arch Math Logic 28, 91–98 (1989). https://doi.org/10.1007/BF01633984
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DOI: https://doi.org/10.1007/BF01633984