A formal definition of self reproducing system is proposed using Petri nets . An actual self-reproducing system is a system that compensates the outflow of its components by reproduction. In a suitable environment eny potential self-reproducing system becomes an actual one.
All living systems are self-reproducing.
Thus, if we want to understand what is life, we need a definition of self-reproduction. However, some definitions are modified here to make it easier to understand. Petri net were designed to represent dynamical systems in which individual objects can change their state, interact with other objects, produce new objects, etc. A place is interpreted as a class of identical objects or as a state of an object. Transitions are interpreted as processes that either change the state of objects or describe interactions among objects.