作者：(美国)杰弗里?A?杰里(Geoffrey A．Jehle) (美国)菲利普?J?瑞尼(Philip J．Reny)
杰弗里?A?杰里（Geoffrey A．Jehle），1983年毕业于普林斯顿大学，获博士学位。目前任美国瓦瑟学院（Vassar College）经济学教授，曾在普林斯顿大学、耶鲁大学、欧洲工商管理学院等学校任教。
In the first two chapters of this volume,we will explore the essential features of modern consumer theory-a bedrock foundation on which so many theoretical structures in economics are built.Some time later in your study of economics,you will begin to notice just how central this theory is to the economist’s Way of thinking.Time and time again you Will hear the echoes of consumer theory in virtually every branch of the discipline-how it is conceived,how it is constructed,and how it is applied.
1.1 PRIMITIVE NOTIONS
There are four building blocks in any model of consumer choice.They are the consumption set,the feasible set,the preference relation,and the behavioural assumption.Each is conceptually distinct from the others.though it is quite common sometimes to lose sight of that fact.This basic structure is extremely general,and so,very flexible.By specifying the form each of these takes in a given problem,many different situations involving choice can be formally described and analysed.Although we will tend to concentrate here on specific formalisations mat have come to dominate economists’ view of an individual consumer Sbehaviour,it is well to keep in mind that‘consumer theory’per se is in tact a very nch and flexible theory of choice.
The notion of a consumption set is straightforward.We let the consumption set,X,represent the set of all alternatives,or complete consumption plans,that the consumer can conceive-whether some of them will be achievable in practice or not.What we intend to capture here is the universe of alternative choices over which the consumer’s mind is capable of wandering,unfettered by consideration of the realities of his present situatmn.The consumption set is sometimes also called the choice set.