Publication Details
Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata
Bouajjani Ahmed (UPAR7)
Holík Lukáš, doc. Mgr., Ph.D. (DITS FIT BUT)
Kaati Lisa (Uppsala)
Vojnar Tomáš, prof. Ing., Ph.D. (DITS FIT BUT)
finite tree automata, simulation, size reduction, combination of simulation relations
We address the problem of computing simulation relations over tree automata. In particular, we consider downward and upward simulations on tree automata, which are, loosely speaking, analogous to forward and backward relations over word automata. We provide simple and efficient algorithms for computing these relations based on a reduction to the problem of computing simulations on labelled transition systems. Furthermore, we show that downward and upward relations can be combined to get relations compatible with the tree language equivalence, which can subsequently be used for an efficient size reduction of nondeterministic tree automata. This is of a very high interest, for instance, for symbolic verification methods such as regular model checking, which use tree automata to represent infinite sets of reachable configurations. We provide experimental results showing the efficiency of our algorithms on examples of tree automata taken from regular model checking computations.
@TECHREPORT{FITPUB8636,
author = "A. Parosh Abdulla and Ahmed Bouajjani and Luk\'{a}\v{s} Hol\'{i}k and Lisa Kaati and Tom\'{a}\v{s} Vojnar",
title = "Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata",
pages = 34,
year = 2008,
location = "FIT-TR-2008-001, Brno, CZ",
language = "english",
url = "https://www.fit.vut.cz/research/publication/8636"
}