Rationality and the LeChatelier principle

Conditions that exhaust the implications of rationality (homogeneity, symme try, definiteness) are well known, but these apply under a single set of co nstraints. If a situation can be compared with another situation where extr a constraints are imposed, there are stronger implications. One example is the (local) LeChatelier principle. However, a global LeChatelier principle does not always hold, and this paper shows that it cannot always hold in an y nondegenerate problem. Despite this, a global LeChatelier principle in ex pectation is shown to apply with weak conditions on the density underlying the expectation. This principle is implied by and exhausts the implications of rationality. (C) 1999 Academic Press.