The essays in this monograph are on refutable economic models. In fact,
we limit attention to semi-algebraic economic models. These are economic
models defined by a finite family of multivariate polynomial inequalities and
equations. The parameters in our models are derived from observable market
data and the unknowns include unobservable theoretical constructs such as
utility levels of consumers or marginal costs of firms, unobservable individual
choices on the part of households and firms, and unobservable shocks to tastes
or technology.