Economic models reveal multiple equilibria, challenging traditional optimization approaches.
The article discusses how economic equilibria are solutions to fixed point problems, not convex optimization problems. This can make equilibria hard to compute and lead to multiple equilibria in a model economy. The researchers explore these issues in various economies, including those with infinite goods, time, uncertainty, and externalities. The study provides insights into economies with large numbers of goods and extends the analysis to economies with distortionary taxes and externalities.