Multi-buffer simulations: Decidability and complexity

We study the decidability and complexity of multi-buffer simulations and obtain the following results: P-completeness for fixed bounded buffers, EXPTIME-completeness in case of a single unbounded buffer and high undecidability (in the analytic hierarchy) with two buffers of which at least one is unbounded. We also consider a variant in which the buffers are kept untouched or flushed and show PSPACE-completeness for the single-buffer case.