Note that the elastic demand model described above is related closely to the well-known
spatial price equilibrium models of Samuelson (1952), Takayama and Judge (1971), and
Florian and Los (1982). Indeed, as demonstrated by Dafermos and Nagurney (1985) in the
context of a single commodity, and, subsequently, by Dafermos (1986) in the case of multiple
commodities, spatial price equilibrium problems are isomorphic to transportation network
equilibrium problems over appropriately constructed networks. Hence, the well-developed
theory of transportation networks can be transferred to the study of commodity flows in
the case of spatial price equilibrium in which the equilibrium production, consumption,
and commodity trade flows are to be determined satisfying the equilibrium conditions that