A feasible allocation (i.e. a set of consumption plans, one for each consumer, and a set of production plants, one for each potential firm, such that demand equals supply for each commodity and each type of labour), a price vector for physical good and, within each firm, a set of weights defining value shares for the different types of labohr, define a competitive equilibrium, provided two conditions are met. Firstly, the production plan of every potential firm must yield maximum value added per worker, given the prices and labohr weights. Secondly, the consumption plan of every consumer must be best for his preferences over the budget set defined by prices, unit shares in value added and his initial resources.