and it might succeed or might not succeed you might have a model for that so you might say if the doors already open and or in this case closed the robot tries to close the door doors already open well 10% chance it'll just stay open because it fails 90% chance it managed to close it if it's already closed and it will keep it closed okay that's a model that might or might not be correct but these are the kind of models that we're going to be working with such that we can do calculations about possible states of the world based