Recherches et rapports sur les mathématiques

Solution Concepts and Equilibria

Martin S. Andersen

In the Prisoner’s Dilemma, the result we’ve represented as indicating
mutual defection, was once stated to be the ‘solution’ to the game.
Following the conventional exercise in economics, sport theorists
refer to the options of video games as equilibria. Philosophically
minded readers will choose to pose a conceptual query proper here:
What is ‘equilibrated’ about some sport consequences such that we
are encouraged to name them ‘solutions’? When we say that a bodily
device is in equilibrium, we imply that it is in a steady state, one in
which all the causal forces inner to the device stability every different
out and so go away it ‘at rest’ till and except it is perturbed by using the
intervention of some exogenous (that is, ‘external’) force. This is what
economists have historically intended in speak me about ‘equilibria’;
they examine monetary structures as being networks of jointly
constraining (often causal) relations, simply like bodily systems, and
the equilibria of such structures are then their endogenously secure
states. (Note that, in each bodily and monetary systems, endogenously
secure states may in no way be immediately discovered due to the
fact the structures in query are by no means remoted from exogenous
influences that go and destabilize them. In each classical mechanics
and in economics.