 
Summary: Simulation is Decidable for Onecounter Nets
(Extended Abstract)
Parosh Aziz Abdulla
Dept. of Computer Systems
P.O. Box 325
S751 05 Uppsala, Sweden
parosh@docs.uu.se
KŻarlis ź
CerŻans
Institute of Mathematics
and Computer Science
University of Latvia
karlis@cclu.lv
Abstract
We prove that the simulation preorder is decidable for the class of onecounter nets. A onecounter
net consists of a finitestate machine operating on a variable (counter) which ranges over the natural
numbers. Each transition can increase or decrease the value of the counter. A transition may not be
performed if this implies that the value of the counter becomes negative. The class of onecounter
nets is computationally equivalent to the class of Petri nets with one unbounded place, and to
the class of pushdown automata where the stack alphabet is restricted to one symbol. To our
