Ultimately, the cost function will depend on the desired task.
This depends on the cost function and the model.
The edge costs are defined based on a cost function.
Taking a section (hyperplane) across the cost function, gives us a picture like 2.5b.
The cost functions may be the same or different among firms.
In this case it is symmetrical to firm 1's as they have the same cost function.
Subadditivity is an essential property of some particular cost functions.
All these methods work by finding the biggest or smallest answer to a cost function.
In fact, it might even be possible to construct separate cost functions.
Therefore, the players maximize the mathematical expectation of the cost function.