This paper applies microeconomic foundations to construct a

\representative agent". Herzberg [12] constructed a representative

utility function for finite-dimensional social decision problems and

since the decision problems of macroeconomic theory are typically

infinite-dimensional, Herzberg's original result is insufficient for many

applications. We therefore generalise his result by allowing the social

alternatives to belong to a general reflexive Banach space and provide

sufficient conditions for our new results to be satisfied in economic

applications.