Macroeconomics 9th Edition by David Colander

Exercise 33

Consider the following economic principles held by Classical economists: (1) Short-run problems are temporary glitches that are solved by the market; (2) The economy always returns to its potential in the long run; and (3) Unemployment is the result of institutional barriers to the market.
a.hat are Keynes's criticisms of these economic principles
b.hy did he believe that they were wrong (Post-Keynesian)