A uniform universal CREW PRAM
The universality of the Parallel Random-Access Machines is usually defined by simulating universal Turing machines or boolean networks. These definitions are well-suited if we are interested in evaluating the complexity of algorithms but it is not as good if we want to deal with computability. We propose in this paper another definition for the universality of the Parallel Random-Access Machines based on cellular automata and we discuss the advantages and the drawbacks of this simulation. We prove that there exists a Concurrent-Read Exclusive-Write Parallel Random-Access Machine which is capable of simulating any given cellular automaton in constant time. We then derive to the definition of complexity classes for the Parallel Random-Access Machines and for cellular automata.
KeywordsCellular Automaton Turing Machine Global Memory Boolean Network Cellular Automaton Model
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