The Market for Lemons car. This, in turn, motivates the owners of moderately good cars not to sell, and so on. The result is that a market in which there is asymmetric information with respect to quality shows characteristics similar to those described by Gresham's Law: the bad drives out the good. (Although Gresham's principle applies more specifically to exchange rates, modified analogies can be drawn.) Akerlof considers a situation in which demand "D" for used cars depends on the cars price "p" and quality "µ" = "µ"("p") and the supply depends on price alone. Economic equilibrium is given by "S"("p") = "D"("p","µ") and
Say's law real shocks cause recessions and that the market responds efficiently to these real economic shocks. Paul Krugman dismisses Say's law as, "at best, a useless tautology when individuals have the option of accumulating money rather than purchasing real goods and services". It is not easy to say what exactly Say's law says about the role of money apart from the claim that recession is not caused by lack of money. The phrase "products are paid for with products" is taken to mean that Say has a barter model of money; contrast with circuitist and post-Keynesian monetary theory. One can read