A comparative analysis of the two surpluses Besides the marxist concept of surplus, two notions of surplus are widely used by economists : the microeconomic surplus and the surplus of global factor productivity. After recalling their respective definition, the concepts will be contrasted with respect to the magnitude of the considered variations (infinitesimal or finite), the relation between the states under comparison (alternative or successive), the level of aggregation at which they are defined (whole society or firni), the order of sequence between their creation and their distribution (one way or another), their conceptual source (theory or business accounts), their use for economic analysis (a priori or a posteriori). The conclus...