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arXiv 2405.02232cs.CC
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从证明复杂性到电路复杂性:经由交互式协议

From Proof Complexity to Circuit Complexity via Interactive Protocols

Noel Arteche, Erfan Khaniki, Ján Pich, Rahul Santhanam

AI总结:

本文证明:若隐式扩展弗雷格系统iEF能高效证明标准去随机化假设,则iEF证明长度的超多项式下界可推出#P不在FP/poly中,从而在证明复杂性与电路复杂性之间建立条件性联系。

摘要:

复杂性理论中的一个民间共识怀疑,针对 $\mathbf{NC}^1$ 或 $\mathbf{P}/\operatorname{poly}$ 的电路下界——目前尚不可及——是证明诸如 Frege 或 Extended Frege 等系统的强证明复杂性下界的必要步骤。然而,正式建立这种联系本身已经令人生畏,因为它将蕴含突破性的分离结果 $\mathbf{NEXP} \not\subseteq \mathbf{P}/\operatorname{poly}$,正如 Pich 和 Santhanam(2023)最近所观察到的。我们针对 Krajíček(The Journal of Symbolic Logic, 2004)引入的隐式扩展弗雷格证明系统($\mathsf{iEF}$)条件性地展示了这样一种联系,该系统能够形式化当代复杂性理论的大部分内容。特别地,我们证明:如果 $\mathsf{iEF}$ 能够高效地证明标准的去随机化假设——即某个具体布尔函数对次指数规模电路而言在平均情形下是困难的,那么任何关于 $\mathsf{iEF}$ 证明长度的超多项式下界都蕴含 $\\#\mathbf{P} \not\subseteq \mathbf{FP}/\operatorname{poly}$(这反过来又将蕴含例如 $\mathbf{PSPACE} \not\subseteq \mathbf{P}/\operatorname{poly}$)。我们的证明利用了在 $\mathsf{iEF}$ 内部对 Lund、Fortnow、Karloff 和 Nisan(Journal of the ACM, 1992)的 sum-check 协议可靠性的形式化。这对 $\mathsf{iEF}$ 中电路上界的自可证性具有推论。有趣的是,进一步改进我们的结果似乎需要在构造具有更高效证明者的交互式证明系统方面取得进展。

英文摘要:

Folklore in complexity theory suspects that circuit lower bounds against $\mathbf{NC}^1$ or $\mathbf{P}/\operatorname{poly}$, currently out of reach, are a necessary step towards proving strong proof complexity lower bounds for systems like Frege or Extended Frege. Establishing such a connection formally, however, is already daunting, as it would imply the breakthrough separation $\mathbf{NEXP} \not\subseteq \mathbf{P}/\operatorname{poly}$, as recently observed by Pich and Santhanam (2023). We show such a connection conditionally for the Implicit Extended Frege proof system ($\mathsf{iEF}$) introduced by Krajíček (The Journal of Symbolic Logic, 2004), capable of formalizing most of contemporary complexity theory. In particular, we show that if $\mathsf{iEF}$ proves efficiently the standard derandomization assumption that a concrete Boolean function is hard on average for subexponential-size circuits, then any superpolynomial lower bound on the length of $\mathsf{iEF}$ proofs implies $\#\mathbf{P} \not\subseteq \mathbf{FP}/\operatorname{poly}$ (which would in turn imply, for example, $\mathbf{PSPACE} \not\subseteq \mathbf{P}/\operatorname{poly}$). Our proof exploits the formalization inside $\mathsf{iEF}$ of the soundness of the sum-check protocol of Lund, Fortnow, Karloff, and Nisan (Journal of the ACM, 1992). This has consequences for the self-provability of circuit upper bounds in $\mathsf{iEF}$. Interestingly, further improving our result seems to require progress in constructing interactive proof systems with more efficient provers.

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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