A direct construction of finite state automata for pushdown store languages. (English) Zbl 1388.68171

Geffert, Viliam; Malcher, Andreas; Meckel, Katja; Mereghetti, Carlo; Palano, Beatrice

Jürgensen, Helmut (ed.) et al., Descriptional complexity of formal systems. 15th international workshop, DCFS 2013, London, ON, Canada, July 22–25, 2013. Proceedings. Berlin: Springer (ISBN 978-3-642-39309-9/pbk). Lecture Notes in Computer Science 8031, 90-101 (2013).

Summary: We provide a new construction of a nondeterministic finite automaton (NFA) accepting the pushdown store language of a given pushdown automaton (PDA). The resulting NFA has a number of states which is quadratic in the number of states and linear in the number of pushdown symbols of the given PDA. Moreover, we prove the size optimality of our construction. Beside improving some results in the literature, our approach represents an alternative and more direct proof of pushdown store language regularity. Finally, we give a characterization of the class of pushdown store languages.
For the entire collection see [Zbl 1268.68025].

MSC:

68Q45

Formal languages and automata

Keywords:

pushdown automata; pushdown store languages; descriptional complexity