The complexity of tensor calculus

The complexity of tensor calculus
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张量微积分的复杂性

DOI:
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发表时间:
2000
期刊:
Proceedings 15th Annual IEEE Conference on Computational Complexity
影响因子:
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通讯作者:
P. McKenzie
P. McKenzie
中科院分区:
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文献类型:
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作者:
C. Damm;M. Holzer;P. McKenzie

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半环上的张量演算与复杂性有关 理论以意想不到的方式。首先,计算良型张量 具有显式张量项的公式对于$igoplusP$,对于NP, 当半环变化时,实际上是矩阵的永久性 可以表示为张量公式的值, Berkowitz定理表示行列式的方式。第二,限制 张量公式显示为捕获类LOGCFL和 NL,其平价对应物$igoplusLOGCFL$和$IgoplusL$和其他几种 数课最后,已知的内含物$NP/多子集 igoplusP/poly$,$LOGCFL/poly subseteq igoplusLOGCFL/poly$和$NL/poly subseteq igoplusL/poly$, 在文献中有零散的证据(Valiant & Vazirani 1986; Gál & Wigderson 1996),表明遵循新的特征 在一个单一的打击。作为中间工具,我们定义并使用 半环$ mathcal{S}$上代数图灵机的自然概念。
AbstractTensor calculus over semirings is shown relevant to complexity theory in unexpected ways. First, evaluating well-formed tensor formulas with explicit tensor entries is shown complete for $igoplusP$, for NP, and for #P as the semiring varies. Indeed the permanent of a matrix is shown expressible as the value of a tensor formula in much the same way that Berkowitz’s theorem expresses its determinant. Second, restricted tensor formulas are shown to capture the classes LOGCFL and NL, their parity counterparts $igoplusLOGCFL$ and $igoplusL$, and several other counting classes. Finally, the known inclusions $NP/poly subseteq igoplusP/poly$, $LOGCFL/poly subseteq igoplusLOGCFL/poly$, and $NL/poly subseteq igoplusL/poly$, which have scattered proofs in the literature (Valiant & Vazirani 1986; Gál & Wigderson 1996), are shown to follow from the new characterizations in a single blow. As an intermediate tool, we define and make use of the natural notion of an algebraic Turing machine over a semiring $ mathcal{S}$.