Parallel communicating grammar systems, or PC grammar systems for short,
have been invented to model a certain type of cooperation: the so-called
class room model.
Here a group of experts, modelled by grammars, work together in order to produce a document,
that is, an output word.
These experts work on their own, but synchronously,
and they are able to exchange information on request.
In the literature many different types and variants of PC grammar systems
have been studied, and the notion of parallel communicating systems has also
been carried over to various types of automata.
For example, PC systems of finite-state acceptors and
PC systems of pushdown automata have been studied.
Here we continue the study of these systems, and we extend the notion
of PC system to restarting automata.
Our aim is to develop a better understanding of the interaction of the
local computations of restarting automata and the communication that
takes place between the various components of a PC system.