Probabilistic Automata with Isolated Cut-Points
نویسندگان
چکیده
We consider various decision problems for probabilistic finite automata (PFA)s with isolated cut-points. Recall that a cut-point x is said to be isolated for a PFA if the acceptance probability of all finite strings is bounded away from x. First we establish the exact level of undecidability of the problem of determining if a cut-point is isolated; we show this problem to be Σ2-complete. Next we introduce a new class of PFAs called eventually weakly ergodic PFAs that generalize ergodic and weakly ergodic PFAs. We show that the emptiness and universality problem for these PFAs is decidable provided the cut-point is isolated.
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