Petri-Net and Augmented-Petri-Net
A simple graph representation of a Petri-net is illustrated in
Figure 1. The graph contains two types of nodes: circles (called
places )
and bars (called
transitions ).
These nodes are connected by directed arcs
from places to transitions and from transitions to places.
If an arc is directed from node i to node j (either from a place
to a transition or a transition to a place), then i is an
input
to j, and j is an
output
of i. In Figure 1, for example, place p1 is an input to transition
t2, while places p2 and p3 are outputs of transition t2.
Figure 1. A simple graph representation of the Petri net.