Mario Chiari

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We investigate the problem how to lift the non-8 b 1 ()-conservativ-ity of T 2 2 () over S 2 2 () to the expected non-8 b i ()-conservativity of T i+1 2 () over S i+1 2 (), for i > 1. We give a non-trivial reenement of the "lifting method" developed in 4, 8], and we prove a suucient condition on a 8 b 1 (f)-consequence of T2(f) to yield the non-conservation(More)
We investigate the possibility to characterize (multi)functions that are b i-deenable with small i (i = 1; 2; 3) in fragments of bounded arithmetic T2 in terms of natural search problems deened over polynomial-time structures. We obtain the following results: 1. A reformulation of known characterizations of (multi)functions that are b 1-and b 2-deenable in(More)
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