
Opposite concept:

1. Sink Place: A sink place is a place where all arrows enter or exit a net, indicating that the net is not connected to other nets.
2. Delayed Transition: A delayed transition occurs when a transition cannot fire immediately due to a condition on its input.

General concept:

1. Petri Net with Constraints: A Petri net with constraints adds additional conditions or rules to the traditional Petri net model, allowing for more complex and nuanced modeling of systems. Examples of constraints include resource availability, time-based constraints, and conditional dependencies.