TOULOUSE – For the last half-century, the world’s leading universities have taught microeconomics through the lens of the Arrow-Debreu model of general competitive equilibrium. The model, formalizing a central insight of Adam Smith’s The Wealth of Nations, embodies the beauty, simplicity, and lack of realism of the two fundamental theorems of competitive equilibrium, in contrast to the messiness and complexity of modifications made by economists in an effort to capture better the way the world actually functions.