On Minimization and Learning of Deterministic $ω$-Automata in the Presence of Don't Care Words

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Löding, Christof, Stachon, Max Philip
Format: Preprint
Published: 2022
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866915920702603264
author Löding, Christof
Stachon, Max Philip
author_facet Löding, Christof
Stachon, Max Philip
contents We study minimization problems for deterministic $ω$-automata in the presence of don't care words. We prove that the number of priorities in deterministic parity automata can be efficiently minimized under an arbitrary set of don't care words. We derive that from a more general result from which one also obtains an efficient minimization algorithm for deterministic parity automata with informative right-congruence (without don't care words). We then analyze languages of don't care words with a trivial right-congruence. For such sets of don't care words it is known that weak deterministic Büchi automata (WDBA) have a unique minimal automaton that can be efficiently computed from a given WDBA (Eisinger, Klaedtke 2006). We give a congruence-based characterization of the corresponding minimal WDBA, and show that the don't care minimization results for WDBA do not extend to deterministic $ω$-automata with informative right-congruence: for this class there is no unique minimal automaton for a given don't care set with trivial right congruence, and the minimization problem is NP-hard. Finally, we extend an active learning algorithm for WDBA (Maler, Pnueli 1995) to the setting with an additional set of don't care words with trivial right-congruence.
format Preprint
id arxiv_https___arxiv_org_abs_2211_08787
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On Minimization and Learning of Deterministic $ω$-Automata in the Presence of Don't Care Words
Löding, Christof
Stachon, Max Philip
Formal Languages and Automata Theory
F.1.1; F.4.3
We study minimization problems for deterministic $ω$-automata in the presence of don't care words. We prove that the number of priorities in deterministic parity automata can be efficiently minimized under an arbitrary set of don't care words. We derive that from a more general result from which one also obtains an efficient minimization algorithm for deterministic parity automata with informative right-congruence (without don't care words). We then analyze languages of don't care words with a trivial right-congruence. For such sets of don't care words it is known that weak deterministic Büchi automata (WDBA) have a unique minimal automaton that can be efficiently computed from a given WDBA (Eisinger, Klaedtke 2006). We give a congruence-based characterization of the corresponding minimal WDBA, and show that the don't care minimization results for WDBA do not extend to deterministic $ω$-automata with informative right-congruence: for this class there is no unique minimal automaton for a given don't care set with trivial right congruence, and the minimization problem is NP-hard. Finally, we extend an active learning algorithm for WDBA (Maler, Pnueli 1995) to the setting with an additional set of don't care words with trivial right-congruence.
title On Minimization and Learning of Deterministic $ω$-Automata in the Presence of Don't Care Words
topic Formal Languages and Automata Theory
F.1.1; F.4.3
url https://arxiv.org/abs/2211.08787