منابع مشابه
Independent Instances for Some Undecidable Problems
— In this note we prove the existence of effectively independent instances (with respect to an arbitrary recursively axiomatizable, consistent, intuitively true and sufficiently rich theory) for some well-known undecidable problems including the Emptiness Problem, the Finiteness Problem, the Totality Problem, the Halting Problem and the Post Correspondence Problem. Applications in the Theory of...
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Inhibitors of fibrinolysis may be divided into naturally circulating inhibitors and antifibrinolytic agents. Natural inhibitors are present in plasma and are components of blood cells, especially platelets. Several types of antifibrinolytic activity can be distinguished: antiplasmin activity, and anti-activator activity against streptokinase, urokinase, and tissue activator induced plasminogen ...
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Tovey [10] showed that it is NP-hard to decide the satisfiability of 3-SAT instances in which every variable occurs four times, while every instance of 3-SAT in which each variable occurs three times is satisfiable. We explore the border between these two problems. Answering a question of Iwama and Takaki, we show that, for every fixed k ≥ 0, there is a polynomial time algorithm to determine th...
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Two types of attacking the RSA cryptosystem are discussed. The rst aims at a careless choice of the primes p and q, which are the basis of RSA security. Choosing these primes carefully can prevent the cryptosystem from this type of attack. The second aims at special instances of RSA-based cryptographical protocols. Speciic properties of these protocols enable users of the system or even outside...
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Compressibility regards the reduction the length of the input, or of some other parameter, preserving the solution. Any 3-SAT instance on N variables can be represented by O(N) bits. [4] proved that the instance length in general cannot be compressed to O(N3−!) bits under the assumption NP !⊆ coNP/poly, which implies that the polynomial hierarchy collapses. This note initiates and puts forward ...
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ژورنال
عنوان ژورنال: The Journal of Geology
سال: 1905
ISSN: 0022-1376,1537-5269
DOI: 10.1086/621214