----------------- HES POSTING ----------------- I think that Professor Lipsey's point about advanced, or at least intermediate undergrad texts, is all too well taken. I have the impression that questions about orthodox viewpoints may be even less welcome at that level than at the Principles level, where at least doubts can be snuck in by talking about various real world policy problems. A very stupid but consistent way to bring in a downward sloping AD curve, although not of much use at the Principles level, is to assume a weak monetarist classical world in which V is constant but money neutrality does not hold. This gives an AD curve that is a rectangular hyperbola for a fixed nominal GDP, with the level of the GDP given by the money supply. There were papers in the 80s that took such an approach. In the first edition of his Principles text, Colander pointed out that the AD curve can be vertical, a point I have also made in published work. But, I gather that market pressure through his publisher forced him to back off that rather interesting line. Barkley Rosser ------------ FOOTER TO HES POSTING ------------ For information, send the message "info HES" to [log in to unmask]