Terminological Inconsistencies of "Elasticity of Substitution," "Substitution Curve," and "Marginal Rate of Substitution": A Correction

The present paper seeks to correct the inconsistencies of the three terms: (i) "elasticity of substitution" ( ES ), (ii) "substitution curve" ( SC ), and (iii) "marginal rate of substitution" ( MRS ). Such inconsistencies persist since their introduction in the 1930s. The correction of such inconsistencies can be executed in terms of Konar's (2009, 2012) "isoquant substitution curve" ( IQSC ) and "isocost substitution curve" ( ICSC ).