 
Summary: Rautomata
Parosh Aziz Abdulla, Pavel Krcal, and Wang Yi
Department of Information Technology,
Uppsala University, Sweden
Email: {parosh,pavelk,yi}@it.uu.se
Abstract. We introduce Rautomata a model for analysis of systems
with resources which are consumed in small parts but which can be re
plenished at once. An Rautomaton is a nite state machine which oper
ates on a nite number of unbounded counters (modeling the resources).
The values of the counters can be incremented, reset to zero, or left
unchanged along the transitions. We dene the language accepted by an
Rautomaton relative to a natural number D as the set of words allowing
a run along which no counter value exceeds D. As the main result, we
show decidability of the universality problem, i.e., the problem whether
there is a number D such that the corresponding language is universal.
The decidability proof is based on a reformulation of the problem in
the language of nite monoids and solving it using the factorization for
est theorem. This approach extends the way in which the factorization
forest theorem was used to solve the limitedness problem for distance
automata in [Sim94]. We also show decidability of the nonemptiness
