I discuss the role of economic theory in empirical work in development economics with special emphasis on general equilibrium and political economy considerations. I argue that economic theory plays (should play) a central role in formulating models, estimates of which can be used for...

We revisit the Cournot–Bertrand debate in the light of Cournot, Edgeworth and Launhardt, tracing back to Launhardt the origin of price competition in duopoly models with constant returns to scale. Then, we discuss the formalisation of consumer utility function for differentiated products,...

The notion of solution plays a crucial role in the conceptual system of Léon Walras, the founder of General Equilibrium Theory (GET). In this paper, after introducing the two solution concepts employed by Walras in the development of his version of GET, respectively called the "theoretical" and...