We discuss the existence of equilibria in ecomomies with indivisible goods. The reasons for which existence of equilibria obtains or not are described. We discuss previous papers on this topic whose results are based on the assumption that goods are gross substitutes. Alternatively in this paper...

In the paper we give two characterizations of choice functions satisfying the outcast condition. The first one is given in order terms, and the second (algebraic) one is given in terms of an operation on the set of stable menus. We investigate implications of associativity of the operation as...