The Wong-Viner Envelope Theorem on the equality of long-run and short-run marginal costs (LRMC and SRMC) is reformulated for convex but generally nondifferentiable cost functions. The marginal cost can be formalized as the multi-valued subdifferential a.k.a. the subgradient set but, in itself,...

Jim Tobin, who died on March 11, 2002 at the age of 84, was one of giants of economics of the second half of the twentieth century and the greatest macroeconomist of his generation. Tobin’s influence on macroeconomic theory is so pervasive - so much part of our professional ‘acquis’ - that...