Volume 1, No. 3, December 2002 Back Duality and the Geometry of the Income and Substitution Effects Michael J. Panik Faculty of Economics, University of Hartford, U.S.A. Abstract The geometry of the Hicks-Slutsky income and substitution effect is framed in terms of the consumer’s expenditure function and expenditure equation and thus can be studied with-out resorting to the indifference map of a direct utility function. Key words: duality; income/substitution effect; expenditure function JEL classification: D1; D6 Back