This is the first property in a flexible approach to microeconomic theory that dispenses with the Implicit Function Theorem to derive sets of “comparative statics.” Perverse results that violate the “positive response” in voting-type situations are avoided in a criterion in social choice theory named for this property. In Angrist and Imbens’s local average treatment effect interpretation of instrumental variables, this property names the assumption that there are no “defiers.” In consumer theory, an assumption named (15[1])for this property is often weakened to (*) local non-satiation. An economic agent has preferences weakly described by this property (-5[1])if they prefer a bundle (-5[1])with (-5[1])more of all goods. (-5[1])For 10 points, (-5[1])name this property, which refers to a mathematical function (10[2])whose output either preserves (10[1])or reverses the order of its input. ■END■ (10[1]0[6])