On the complexity of learning minimum time-bounded Turing machines
On the complexity of learning minimum time-bounded Turing machines
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关于学习最小时间有限图灵机的复杂性
DOI:
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发表时间:
1990
期刊:
影响因子:
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通讯作者:
K. Ko
中科院分区:
文献类型:
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作者:
K. Ko
The following problems about time-bounded program-size complexity are studied: (1) for a given string x, a size bound s, and a time bound t, whether there exists a Turing machine of size less than or equal to s that prints x in t moves; (2) for two given finite sets Y and Z of strings, a size bound s, and a time bound t, whether there exists a Turing machine of size less than or equal to s that operates in time t and accepts all $y in Y$ and rejects all $z in Z$. These problems are fundamental in complexity theory and feasible learning theory. The complexity of these problems is apparently between P and $NP$, but appears very difficult to classify precisely. These problems are attacked by the approach of relativization. It is shown that for certain variations of the problems, they could be either polynomial-time computable or not polynomial-time computable, depending on different oracles. Furthermore, there are oracles relative to which they are not complete for $NP$ under the polynomial-time Turing red...