Exact descriptional complexity of determinization of input-driven pushdown automata

Fuente: arXiv
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Autore principale: Martynova, Olga
Natura: Preprint
Pubblicazione: 2024
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author Martynova, Olga
author_facet Martynova, Olga
contents The number of states and stack symbols needed to determinize nondeterministic input-driven pushdown automata (NIDPDA) working over a fixed alphabet is determined precisely. It is proved that in the worst case exactly 2^{n^2} states are needed to determinize an n-state NIDPDA, and the proof uses witness automata with a stack alphabet Γ= {0,1} working on strings over a 4-symbol input alphabet (Only an asymptotic lower bound was known before in the case of a fixed alphabet). Also, the impact of NIDPDA determinization on the size of stack alphabet is determined precisely for the first time: it is proved that s(2^{n^2}-1) stack symbols are necessary in the worst case to determinize an n-state NIDPDA working over an input alphabet of size s+5 with s left brackets (The previous lower bound was only asymptotic in the number of states and did not depend on the number of left brackets).
format Preprint
id arxiv_https___arxiv_org_abs_2404_10516
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exact descriptional complexity of determinization of input-driven pushdown automata
Martynova, Olga
Formal Languages and Automata Theory
The number of states and stack symbols needed to determinize nondeterministic input-driven pushdown automata (NIDPDA) working over a fixed alphabet is determined precisely. It is proved that in the worst case exactly 2^{n^2} states are needed to determinize an n-state NIDPDA, and the proof uses witness automata with a stack alphabet Γ= {0,1} working on strings over a 4-symbol input alphabet (Only an asymptotic lower bound was known before in the case of a fixed alphabet). Also, the impact of NIDPDA determinization on the size of stack alphabet is determined precisely for the first time: it is proved that s(2^{n^2}-1) stack symbols are necessary in the worst case to determinize an n-state NIDPDA working over an input alphabet of size s+5 with s left brackets (The previous lower bound was only asymptotic in the number of states and did not depend on the number of left brackets).
title Exact descriptional complexity of determinization of input-driven pushdown automata
topic Formal Languages and Automata Theory
url https://arxiv.org/abs/2404.10516