arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.06854math.LO
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关于对、集合和证明大小的拉姆齐定理

Ramsey's theorem for pairs, collection, and proof size

Leszek Aleksander Kołodziejczyk, Tin Lok Wong, Keita Yokoyama

摘要:

我们证明了任何证明的$\forall Σ^0_2$句子的理论$\mathrm{WKL}_0 + \mathrm{RT}^2_2$可以翻译成证明$\mathrm{RCA}_0$在成本的多项式增加的大小。事实上,$\mathrm{RCA}_0$中的证明可以通过多项式时间算法找到。另一方面,$\mathrm{RT}^2_2$在证明$Σ_1$语句时比弱基理论$\mathrm{RCA}^*_0$有非初等的加速比。我们还表明,$n \ge 0$,证明$Π_{n+2}$句子在$\mathrm{B}Σ_{n+1}+\exp$可以转换成证明在$\mathrm{I}Σ_{n} + \exp$在多项式成本。此外,$\mathrm{B}Σ_{n+1} + \exp$在$\mathrm{I}Σ_{n} + \exp$上的$Π_{n+2}$ -保守性可以在$\mathrm{PV}$中证明,$\mathrm{PV}$是对应于多项式时间计算的有界算术的一个片段。对于$n \ge 1$来说,这回答了Clote,Hájek和Paris的问题。

英文摘要:

We prove that any proof of a $\forall Σ^0_2$ sentence in the theory $\mathrm{WKL}_0 + \mathrm{RT}^2_2$ can be translated into a proof in $\mathrm{RCA}_0$ at the cost of a polynomial increase in size. In fact, the proof in $\mathrm{RCA}_0$ can be found by a polynomial-time algorithm. On the other hand, $\mathrm{RT}^2_2$ has non-elementary speedup over the weaker base theory $\mathrm{RCA}^*_0$ for proofs of $Σ_1$ sentences. We also show that for $n \ge 0$, proofs of $Π_{n+2}$ sentences in $\mathrm{B}Σ_{n+1}+\exp$ can be translated into proofs in $\mathrm{I}Σ_{n} + \exp$ at polynomial cost. Moreover, the $Π_{n+2}$-conservativity of $\mathrm{B}Σ_{n+1} + \exp$ over $\mathrm{I}Σ_{n} + \exp$ can be proved in $\mathrm{PV}$, a fragment of bounded arithmetic corresponding to polynomial-time computation. For $n \ge 1$, this answers a question of Clote, Hájek, and Paris.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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