More on Minimizing Finite Automata with Errors — Nondeterministic Machines

Abstract

We continue our research on minimization problems and related problems for automata w.r.t. to different error profiles, now considering nondeterministic finite automata (NFAs) as inputs. Here the error profiles are almost-equivalence and E-equivalence. We show that the minimization problems and their underlying equivalence problems become PSPACE-complete in most cases. The obtained results nicely fit to the known ones on ordinary NFA minimization, and show a significant difference to the previously obtained results on deterministic finite state machines.