# On the communication complexity of parallel computation

Conference paper

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## Abstract

We argue that the synchronized alternating finite automaton (introduced by Hromkovič et al.) is a viable model for studying the communication complexity of parallel computation. This motivates our study of the classes of languages accepted by synchronized alternating finite automata (SAFA) whose messages are bounded in length by a function *m(n)*. We establish the lower bounds on *m(n)* for some types of SAFA to accept nonregular languages; we also show that these bounds are tight. Next, we establish dense hierarchies of these machines on *m(n)*, and finally we give a characterization of NP in terms of bounded-message multihead SAFA.

## Keywords

Parallel Computation Turing Machine Communication Complexity Computation Tree Finite Automaton
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## Copyright information

© Springer-Verlag Berlin Heidelberg 1993