Fig. 2
From: A methodological approach for using high-level Petri Nets to model the immune system response
Example of the use of a stochastic transition to model the dead of entities that have completed their life cycle. TH cells that have completed their life cycle will be removed from the system. The transition is enabled if and only if the guard condition on the LIFE subset color holds, thus only if the binding on the TH variable (of type TH) is done on a token whose third component element (LIFE) of the product colorset TH is equal to zero (th:3 = 0)