# Revising the Membrane Computing Model for Byzantine Agreement

## Abstract

We refine our earlier version of P systems with complex symbols. The new version, called cP systems, enables the creation and manipulation of high-level data structures which are typical in high-level languages, such as: relations (graphs), associative arrays, lists, trees. We assess these capabilities by attempting a revised version of our previously best solution for the Byzantine agreement problem – a famous problem in distributed algorithms, with non-trivial data structures and algorithms. In contrast to our previous solutions, which use a greater than exponential number of symbols and rules, the new solution uses a *fixed sized* alphabet and ruleset, independent of the problem size. The new ruleset follows closely the conceptual description of the algorithm. This revised framework opens the way to further extensions, which may bring P systems closer to the conceptual Actor model.

### Keywords

Distributed algorithms Byzantine agreement EIG trees Membrane computing P systems cP systems Inter-cell parallelism Intra-cell parallelism Prolog terms and unification Complex symbols Cells with subcells Generic rules Synchronous and asynchronous models Actor model## Notes

### Acknowledgments

We are deeply indebted to the co-authors of our former studies on the Byzantine agreement and to the anonymous reviewers, for their most valuable comments and suggestions.

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