Locality Testing for NFAs is PSPACE-complete
Formal Languages and Automata Theory
2025-11-11 v1
Abstract
The class of local languages is a well-known subclass of the regular languages that admits many equivalent characterizations. In this short note we establish the PSPACE-completeness of the problem of determining, given as input a nondeterministic finite automaton (NFA) A, whether the language recognized by A is local or not. This contrasts with the case of deterministic finite automata (DFA), for which the problem is known to be in PTIME.
Keywords
Cite
@article{arxiv.2511.07361,
title = {Locality Testing for NFAs is PSPACE-complete},
author = {Antoine Amarilli and Mikaël Monet and Rémi De Pretto},
journal= {arXiv preprint arXiv:2511.07361},
year = {2025}
}
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3 pages