Gains and losses at core allocations

The search for a coalition which can possibly improve upon a given allocation and the redistribution of endowments within such a coalition are conducted through the use of prices. Prices permit the expression of how much every agent gains or loses in the allocation. With any feasible allocation one can associate a price system such that either the total loss of all losers does not exceed a certain bound independent of the number of agents or the losers can improve. The definition of gains and losses that we use implies that the total gain is also bounded in core allocations. Our theorem is closely related to that of Vind (1965).