Quasi-Distances and Weighted Finite Automata
We show that the neighbourhood of a regular language \(L\) with respect to an additive quasi-distance can be recognized by an additive weighted finite automaton (WFA). The size of the WFA is the same as the size of an NFA (nondeterministic finite automaton) for \(L\) and the construction gives an upper bound for the state complexity of a neighbourhood of a regular language with respect to a quasi-distance. We give a tight lower bound construction for the determinization of an additive WFA using an alphabet of size five. The previously known lower bound construction needed an alphabet that is linear in the number of states of the WFA.
KeywordsRegular languages Weighted finite automata State complexity Distance measures
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