Equilibrium and quasi-equilibrium existence theorems for a general model without ordered preferences

In previous papers Gale and Mas-Colell (1975) and later Florenzano (1981) obtained a fixed point theorem. Gale and Mas-Colell proved also an existence equilibrium theorem. In this paper I offer a more general fixed point theorem that embodies as special cases the above mentionaed results. The new fixed point theorem is used as a main result in obtaining a general equilibrium theorem in weaker conditions than those of the previous proofs.