Venice on map of italy for In particular, an economy may operate either at its boundary, the PPF, or at its interior, leaving resources unemployed. That notwithstanding, it is a well known theoretical result that, under certain regularity conditions, a competitive economy without externalities or other market failures will indeed operate at the PPF, fully employing the available resources. BIBLIOGRAPHY. Avinash Dixit and Victor Norman, Theory of International Trade (Cambridge University Press, 1980); Paul R. Krugman and Maurice Obstfeld, International Economics: Theory and Policy (Addison-Wesley, 2003); James R. Markusen, et al., International Trade: Theory and Evidence (McGraw-Hill, 1994). Venice on map of italy 2016.