Marshall's notion of the representative firm can be read as a macro notion with some resemblance to Keynes' aggregative concepts. Keynes' notions of aggregate demand and aggregate supply are fashioned after Marshall's definitions of demand and supply. Keynes starts with the Marshallian...

Although it is not possible, in general, to give a macro description of a micro model over the entire state space of the micro model, it is possible to aggregate exactly over a subspace. The set of micro states where aggregation is possible forms the aggregation set. The paper considers the...