Speedup for natural problems and noncomputability
نویسندگان
چکیده
منابع مشابه
Speedup for natural problems and noncomputability
A resource-bounded version of the statement “no algorithm recognizes all non-halting Turing machines” is equivalent to an infinitely often (i.o.) superpolynomial speedup for the time required to accept any (paddable) coNPcomplete language and also equivalent to a superpolynomial speedup in proof length in propositional proof systems for tautologies, each of which implies P 6= NP. This suggests ...
متن کاملSpeedup for Natural Problems
Informally, a language L has speedup if, for any Turing machine (TM) for L, there exists one that is better. Blum [1] showed that there are computable languages that have almost-everywhere speedup. These languages were unnatural in that they were constructed for the sole purpose of having such speedup. We identify an intuitive condition which, like several others in the literature, implies that...
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Informally, a language L has speedup if, for any Turing machine (TM) for L, there exists one that is better. Blum [2] showed that there are computable languages that have almost-everywhere speedup. These languages were unnatural in that they were constructed for the sole purpose of having such speedup. We identify a condition apparently only slightly stronger than P 6= NP which implies that acc...
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In this paper three models of parallel speedup are studied. They are xed-size speedup, xed-time speedup and memory-bounded speedup. The latter two consider the relationship between speedup and problem scalability. Two sets of speedup formulations are derived for these three models. One set considers uneven workload allocation and communication overhead, and gives more accurate estimation. Anoth...
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در این رساله به بررسی رفتار جواب های رده ای از معادلات دیفرانسیل با مشتقات جزیی در دامنه های کراندار می پردازیم . این معادلات به فرم نیم-خطی و غیر خطی برای مسایل مستقیم و معکوس مورد مطالعه قرار می گیرند . به ویژه، تاثیر شرایط مختلف فیزیکی را در مساله، نظیر وجود موانع و منابع، پراکندگی و چسبندگی در معادلات موج و گرما بررسی می کنیم و به دنبال شرایطی می گردیم که متضمن وجود سراسری یا عدم وجود سراسر...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2011
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2010.09.029