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arXiv 2110.06211cs.CCcs.FL
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多项式时间确定性图灵机经由非确定性图灵机的对角化

Diagonalization of Polynomial-Time Deterministic Turing Machines via Nondeterministic Turing Machines

Tianrong Lin

AI总结:

本研究通过通用非确定性图灵机对所有多项式时间确定性图灵机进行对角化,构造出属于NP但不属于P的语言,从而提出P≠NP的证明方法,并论证了对角化技术通常不适用于相对化版本的P与NP问题。

摘要:

对角化技术由 Georg Cantor 发明,用于证明实数比代数数更多,在理论计算机科学中极为关键。在本研究中,我们枚举了所有多项式时间确定性图灵机,并通过通用非确定性图灵机对它们全部进行对角化。由此我们得出,存在一种语言 $L_d$,它不被任何多项式时间确定性图灵机接受,但可被在 $O(n^k)$ 时间内运行的图灵机接受(对于任意 $k\in\mathbb{N}_1$)。基于此,我们进一步证明 $L_d\in\mathcal{NP}$。即,我们提出了证明 $\mathcal{P}$ 与 $\mathcal{NP}$ 不同的方法。同时,我们证明 $\mathcal{P}$ 中存在语言 $L_s$,接受它的机器在所有 $k\in\mathbb{N}_1$ 的时间 $O(n^k)$ 内运行。最后,我们证明若 $\mathcal{P}^O=\mathcal{NP}^O$ 且基于有理基假设,则所有带预言机 $O$ 的多项式时间确定性预言机图灵机集合 $P^O$ 不可枚举,从而表明对角化技术(经由通用非确定性预言机图灵机)通常不适用于 $\mathcal{P}$ 与 $\mathcal{NP}$ 问题的相对化版本。

英文摘要:

The {\em diagonalization technique} was invented by Georg Cantor to show that there are more real numbers than algebraic numbers and is very crucial in {\em theoretical computer science}. In this work, we enumerate all of the polynomial-time deterministic Turing machines and diagonalize against all of them by a universal nondeterministic Turing machine. As a result, we obtain that there is a language $L_d$ not accepted by any polynomial-time deterministic Turing machines but accepted by a nondeterministic Turing machine running within time $O(n^k)$ for any $k\in\mathbb{N}_1$. Based on these, we further show that $L_d\in\mathcal{NP}$. That is, in this work, we present a proof that $\mathcal{P}$ and $\mathcal{NP}$ differ. Meanwhile, we show that there exists a language $L_s$ in $\mathcal{P}$, but the machine accepting it also runs within time $O(n^k)$ for all $k\in\mathbb{N}_1$. Lastly, we show that if $\mathcal{P}^O=\mathcal{NP}^O$ and on some rational base assumptions, then the set $P^O$ of all polynomial-time deterministic oracle Turing machines with oracle $O$ is not enumerable, thus demonstrating that the diagonalization technique ({\em via a universal nondeterministic oracle Turing machine}) will generally {\em not} apply to the relativized versions of the $\mathcal{P}$ versus $\mathcal{NP}$ problem.

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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