Abstract.
We prove that for sufficiently large \(n\), there are tautologies of size \(O(n)\) that require proofs containing \(\Omega( n / \log n )\) lines in axiomatic systems of propositional logic based on the rules of substitution and detachment.
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Received October 19, 1995
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Urquhart, A. The number of lines in Frege proofs with substitution. Arch Math Logic 37, 15–19 (1997). https://doi.org/10.1007/s001530050078
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DOI: https://doi.org/10.1007/s001530050078