Following TER nets, an approach to the modeling of time in high-level Petri nets,
we propose a model of time within (attributed) graph transformation systems where
logical clocks are represented as distinguished node attributes. Corresponding axioms
for the time model in TER nets are generalized to graph transformation systems and
semantic variations are discussed. They are summarized by a general theorem ensuring
the consistency of temporal order and casual dependencies. The resulting notions of
typed graph transformation with time specialize the algebraic double-pushout (DPO)
approach to typed graph transformation. In particular, the concurrency theory of the
DPO approach can be used in the transfer of the basic theory of TER nets.
