In this paper we investigate the nature of rational expectations equilibria for economic epidemiological models. Unlike mathematical epidemiological models, economic epidemiological models can produce regions of indeterminacy or instability around the endemic steady states. We consider SI, SIS,...

Increasing returns to scale and firms' market power are two potential sources of sunspot expectations in neoclassical models. We show that in New Keynesian models, returns to scale and market power can have fundamentally different implications for broad macroeconomic issues, including...

A challenge facing the literature of equilibrium indeterminacy and sunspot-driven business cycle fluctuations based on increasing returns to scale in production is that the required degree of increasing returns for generating indeterminacy can be implausibly large and rise quickly with the...

Syphilis has re-emerged as a global public health issue. In lesser developed countries, millions of people are contracting the disease, which can be fatal without access to proper treatment. In developed countries, prevalence is on the rise and has cycled around endemic levels for decades. We...