Abstract.
For a fixed q ℕ and a given Σ1 definition φ(d,x), where d is a parameter, we construct a model M of 1 Δ0 + ¬ exp and a non standard d M such that in M either φ has no witness smaller than d or phgr; is equivalent to a formula ϕ(d,x) having no more than q alternations of blocks of quantifiers.
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Received: 29 September 1998 / Revised version: 7 November 2001 Published online: 10 October 2002
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ID="⋆" Research supported in part by The State Committee for Scientific Research (Poland), KBN, grant number 2 PO3A 018 13.
RID="⋆"
ID="⋆" Research supported in part by The State Committee for Scientific Research (Poland), KBN, grant number 2 PO3A 018 13.
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Adamowicz, Z., Zbierski, P. On complexity reduction of Σ1 formulas. Arch. Math. Logic 42, 45–58 (2003). https://doi.org/10.1007/s001530200145
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DOI: https://doi.org/10.1007/s001530200145