Sunspots can strictly improve resource allocation in non-convex economies.
Consumption or production externalities, as introduced by Steve Spear and successfully explored in applied work on economic fluctuations by Jess Benhabib, Roger Farmer, Stephanie Schmitt-Groh , Yi Wen and others. Nonconvexities in consumption or production. Translation to be published in Macroeconomic Dynamics as a Vintage Unpublished Paper. This is slightly more general than the JPE version. This is more complete than the RES version.