An original approach to the equilibrium problem in a linear exchange model and its variations are clarified. The conceptual base of this approach is the scheme of polyhedral complementarity suggested by the author for the linear exchange model with fixed budgets [5] and extended later to the general case of the model [6]. It is known that the problem of finding an equilibrium in the linear exchange model can be reduced to the linear complementarity problem [3]. The approach is based on a fundamentally different idea and may be treated as a realization of the main idea of the simplex-method of linear programming. It has no analogs and made it possible to obtain the finite algorithms for some variations of the exchange model. In addition to new algorithms for equilibrium finding, it allows us to reveal a monotonicity property inherent in the models under consideration. This property is analogous with that in linear complementarity problems with positive principal minors of the restriction matrix (class P).

exchange model, economic equilibrium, polyhedral complex, complementarity, monotonicity.