Endogenous city formation with production externalities: Existence of equilibrium

I show that equilibria exist in closed city- system models with production externalities if firms' production possibilities vary continuously with the source of the externality, are constant returns to scale in own inputs, include inaction, and satisfy free disposal; if firms have to employ their own inputs to produce output; if there is a finite number of firm types; and if some standard conditions on preferences and endowments are satisfied. This is the first model to include production externalities in the fully general equilibrium framework required for endogenous city formation. Thus, this result provides formal support for the conjecture that production externalities lead to urban agglomeration.