On the power of multiplication in random access machines
Juris Hartmanis,Janos Simon +1 more
- pp 13-23
TLDR
It is proved that, counting one operation as a unit of time and considering the machines as acceptors, deterministic and nondeterministic polynomial time acceptable languages are the same, and are exactly the languages recognizable in polynomially tape by Turing machines.Abstract:
We consider random access machines with a multiplication operation, having the added capability of computing logical operations on register are considered both as an integer and as a vector of bits and both arithmetic and boolean operations may be used on the same register. We prove that, counting one operation as a unit of time and considering the machines as acceptors, deterministic and nondeterministic polynomial time acceptable languages are the same, and are exactly the languages recognizable in polynomial tape by Turing machines. We observe that the same measure on machines without multiplication is polynomially related to Turing machine time-thus the added computational power due to multiplication in random access machines is equivalent to the computational power which polynomially tape-bounded Turing machine computations have over polynomially time-bounded computations. Therefore, in this formulation, it is not harder to multiply than to add if and only if PTAPE = PTIME for Turing machines. We also discuss other instruction sets for random access machines and their computational power.read more
Citations
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Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer
TL;DR: In this paper, the authors considered factoring integers and finding discrete logarithms on a quantum computer and gave an efficient randomized algorithm for these two problems, which takes a number of steps polynomial in the input size of the integer to be factored.
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Polynomial-Time Algorithms for Prime Factorization and Discrete Logarithms on a Quantum Computer
TL;DR: In this paper, the authors considered factoring integers and finding discrete logarithms, two problems that are generally thought to be hard on classical computers and that have been used as the basis of several proposed cryptosystems.
Proceedings ArticleDOI
Parallelism in random access machines
Steven Fortune,James C. Wyllie +1 more
TL;DR: A model of computation based on random access machines operating in parallel and sharing a common memory is presented and can accept in polynomial time exactly the sets accepted by nondeterministic exponential time bounded Turing machines.
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On uniform circuit complexity
TL;DR: It is argued that uniform circuit complexity introduced by Borodin is a reasonable model of parallel complexity and that context-free language recognition is in NC, the class of polynomial size andPolynomial-in-log depth circuits.
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On Relating Time and Space to Size and Depth
TL;DR: Turing machine space complexity is related to circuit depth complexity, which complements the known connection between Turing machine time and circuit size, thus enabling the related nature of some important open problems concerning Turing machine and circuit complexity to be exposed.
References
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