Comparative Statics and Asset Substitutability/Complementarity in a Portfolio Model: A Dual Approach
This article uses a dual approach to investigate the properties of an n-asset portfolio model. The indirect expected utility and expenditure functions are used to provide an extremely simple derivation of Slutsky equations by obtaining results similar to Roy's Identity and Shephard's Lemma. The substitutability/complementarity relations among assets are investigated, and a number of empirically testable implications are deduced from the properties of the expenditure function.
Dalal, Ardeshir J. "Comparative statics and asset substitutability/complementarity in a portfolio model: a dual approach." The Review of Economic Studies 50, no. 2 (1983): 355-367.