中级微观经济学课件第3章).pdf

Chapter Three Preferences 消费者偏好 Where Are We in the Course? • We are studying the 1st of the three blocks of microeconomics: Consumer behavior, production theory, and market equilibrium • Within the 1st block, we are working on the 2nd of the three components: choice set, preference, and consumer demand What Do We Mean by Preference? (偏好) • It refers to the ordered relationship among alternative choices given by an economic agent. • In most economic literature, consumer preference is treated as the ultimate exogenous element. Preference Relations • Comparing two different consumption bundles, x and y: – strict preference: x is more preferred than is y. – weak preference: x is as at least as preferred as is y. – Indifference: x is exactly as preferred as is y. Notations • ≺ denotes strict preference; ∼ denotes indifference; • ~ denotes weak preference; Preference Relations • x y and y x imply x ∼ y. ~ ~ ≺ • x y and (not y x) imply x y. ~ ~ Assumptions about Preference Relations • Completeness: For any two bundles x and y it is always possible to make the statement that either x y ~ or y x. ~ Assumptions about Preference Relations • Reflexivity: Any bundle x is always at least as preferred as itself; i.e.