With Fisher and Henry, this economist names a framework of option value applied to wildlife preservation. With a French colleague, this economist names a model that states that, for all commodities, there is a set of prices for which aggregate supply equals aggregate demand. An equation written as the negative of the second derivative of utility over the first derivative of utility is named for this economist and John W. Pratt. Freedom from irrelevant alternatives and nondictatorship are conditions that cannot be simultaneously satisfied (10[1])per a theorem named for this economist, which states community preference cannot be determined (10[1])by the preferences of individual voters. For 10 points, a general equilibrium model is named for Gérard Debreu and what American economist who names an “impossibility (10[1])theorem?” ■END■