Publication detail

Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata

HOLÍK, L., VOJNAR, T., ABDULLA, P., BOUAJJANI, A., KAATI, L.

Original Title

Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata

English Title

Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata

Type

presentation

Language

en

Original Abstract

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.

English abstract

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.

Keywords

finite tree automata, simulation, size reduction, combination of simulation relations

Released

09.06.2008

Location

FIT-TR-2008-001, Brno

Pages count

34

URL

Documents

BibTex


@misc{BUT63912,
  author="Lukáš {Holík} and Tomáš {Vojnar} and Parosh {Abdulla} and Ahmed {Bouajjani} and Lisa {Kaati}",
  title="Computing Simulations over Tree Automata: Efficient Techniques for Reducing Tree Automata",
  annote="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.

", chapter="63912", year="2008", month="june", type="presentation" }