Artifact-centric systems are a recent paradigm for represent-
ing and implementing business processes. We present further
results on the verification problem of artifact-centric systems
specified by means of FO-CTL specifications. While the gen-
eral problem is known to be undecidable, results in the lit-
erature prove decidability for artifact systems with infinite
domains under boundedness and conditions such as unifor-
mity. We here follow a different approach and investigate the
general case with infinite domains. We show decidability of
the model checking problem for the class of artifact-centric
systems whose database schemas consist of a single unary
relation, and we show that that the problem is undecidable if
artifact systems are defined by using one binary relation or
two unary relations.