In this paper a general equilibrium model of an economy with price rig
idities and quantity rationing is considered. The equilibria in such a
model are called constrained equilibria. It is well-known that there
exist two so-called trivial constrained equilibria at which every cons
umer keeps his initial endowments. In this paper it is shown that ther
e exists a connected set of constrained equilibria containing both the
se trivial constrained equilibria, hence, there exists a continuum of
constrained equilibria. Moreover, it is shown that all known equilibri
um existence results for the model discussed follow as easy corollarie
s from this result. The proof of the result combines theorems in the a
reas of mathematical programming with those in topology. The result is
shown without using differentiability assumptions and is also extende
d to the case with upper semicontinuous demand correspondences. (C) 19
98 Elsevier Science S.A. All rights reserved.