ABSTRACT
From now on, let Da,b designate the effective demand for (A) in exchange for (B), Db,a the effective demand for (B) in exchange for (A), pa,b the price of (A) in terms of (B) and pb,a the price of (B) in terms of (A). To relate the four unknowns Da,b, Db,a, pa,b, and pb,a we have two equations of effective demand
Da,bFa,b( pa,b), Db,aFb,a( pb,a),
and two equations expressing equality between effective demand and effective offer:
Db,aFa,b pa,b, Da,bDb,a pb,a.
