Polynomial size proofs of the propositional pigeonhole principle
AbstractCook and Reckhow defined a propositional formulation of the pigeonhole principle. This paper shows that there are Frege proofs of this propositional pigeonhole principle of polynomial size. This together with a result of Haken gives another proof of Urquhart's theorem that Frege systems have an exponential speedup over resolution. We also discuss connections to provability in theories of bounded arithmetic.
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2009 ◽
Vol 74
(3)
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pp. 829-860
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2000 ◽
Vol 103
(1-3)
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pp. 155-199
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2007 ◽
Vol 72
(3)
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pp. 959-993
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