The Dornbusch-Fischer-Samuelson model comes from a paper titled first for this concept that extends the classical idea of it to a continuum of goods. Gottfried Haberler’s work on this concept, which Robert Torrens independently discovered, detached it from the earlier labor theory of value. A “revealed” form of this economic concept, which is defined by the Balassa index, is based on flows of goods. A theory that this concept is the (*) main driver of gains from trade, even if one country has higher (10[1])efficiency in all goods, was illustrated with examples of English cloth and Portuguese wine by David Ricardo. For 10 points, name this economic state of having a lower opportunity cost and so being best placed to produce a certain good, unlike in an “absolute” form. ■END■