The identity is the state in the set of stationary states which has the property that when added to another state in the set and then the system is allowed to relax, the system will return to the state to which the identity was added. The identities for different models can be quite different. Refer to the model key to find out which model the identities below are associated with.
Mean field for directed models;
Plots from the avalanche size probability simulations for the different models.
To see the relationships between the perimeter and the area of avalanches in different directed models follow the following links:
