Chapter one：Introduction一、资源的稀缺性与合理配置对于消费者和厂商等微观个体来说，其所拥有的经济资源的稀缺性要求对资源进行合理的配置，从而产生微观经济学的基本问题。
资源配置有两种方式，微观经济学研究市场是如何配置资源，并且认为在一般情况下市场的竞争程度决定资源的配置效率。
二、经济理论或模型的实质微观经济学是实证经济学，它的绝大多数理论和模型都是对微观活动的客观描述，或者是对现实经济观察所做的解释。
由现实抽离出理论,然后再用理论对现实做出解释与分析,这就是经济理论的实质.不同的理论实际上就是对经济现象所做的不同的抽离和解释。
理论模型（model）经济现实（reality)验证解释理论从实际中产生实际对理论的验证三、经济理论模型的三个标准任何一个经济学理论模型都必须满足以下三个标准：（一)要足够简化（no redundant assumption）指假设的必要性。
假设越少模型的适用面越宽。
足够简化还意味着应当使用尽可能简单的方法来解释和说明实际问题，应当将复杂的问题简单化而不是将简单的问题复杂化。
应当正确看待数学方法在经济学中的应用，奠定必要的数学基础.熟练的运用三种经济学语言.（二）内部一致性（internal consistency）这是对理论模型的基本要求，即在一种假设下只能有一种结论。
比如根据特定假设建立的模型只能有唯一的均衡（比如供求模型)；在比较静态分析中，一个变量的变化也只能产生一种结果。
内在一致性保证经济学的科学性，而假设的存在决定了理论模型的局限性。
经济学家有几只手？（三）是否能解决实际问题（relevance）经济学不是理论游戏,任何经济学模型都应当能够解决实际问题。
在这方面曾经有关于经济学本土化问题的讨论。
争论的核心在于经济学是建立在完善的市场经济的基础上的，而中国的市场经济是不完善的，因此能不能运用经济学的理论体系和方法来研究和解决中的问题。
两种观点：一种观点认为经济理论是一个参照系，可以用来对比和发现问题，因此具有普遍的适用性；另一种观点认为中国有自己的国情，需要对经济学进行改造或者使之本土化,甚至有人提出要建立有中国特色的经济学体系。
高级微观经济学讲义：平衡与福利主讲人：邢祖礼西南财经大学经济学院〔2021秋季〕一、教学目的与要求通过本讲，让学生理解部分平衡、一般平衡的根本思想，掌握帕累托最优、超额需求函数、经济核等重要概念，熟悉福利经济学第一定理、第二定理、核定理，可以较为详细的理解平衡的存在性问题。
二、根本内容与课时安排1、部分平衡〔3课时〕2、交换平衡：求解〔2课时〕3、消费：求解克鲁索经济〔2课时〕4、平衡的存在性〔1课时〕5、核与核定理〔2课时〕6、答疑与作业讲解〔2课时〕共计：12课时〔两周〕三、参考书目杰弗瑞.杰里菲利普.瑞尼：?高级微观经济学?，上海财经大学出版社2002年。
:“Microeconomic Theory〞，上海财经大学出版社2005年。
附：讲义的根本内容高级微观经济学讲义:平衡与福利邢祖礼西南财经大学经济学院2021年秋季第一讲：部分平衡分析一、竞争性平衡1、拟线性效用函数Quasi-linear utility function:)(),(i i i i i i x m x m u ϕ+=, i x 是一个消费产品, i m 是其他所产品的支出。
这种函数形式暗含两个假设：(1) x 产品没有收入效应，即x 产品的边际效用独立于收入m ；(2) x 产品的价格不影响其他产品的价格。
通过这两个假设，我们可以得出：其他产品的价格独立于x 产品。
2、需求:)(max i i i x m ϕ+s.t. ∑=-⋅+≤⋅+Jj j j j ij i i i q C q p x p m 1)]([θω (*)从 (*)中, 我们有:i Jj j j j ij i i x p q C q p m ⋅--⋅+=∑=1)]([θω代入目的函数有：∑=-⋅++⋅-Jj j j j ij i i i i x q C q p x p x i1)]([)(max θωϕ0)0(*=⇒≤'i i x p ϕ*()i i x p ϕ'=。
《微观经济学》电子讲稿张衔四川大学经济学院导论1.微观经济学的研究对象与基本假定1。
1微观经济学的研究对象1。
1。
1经济学的定义“经济”一词，在现代汉语中至少有两个定义。
一是指节省、有效率，以较少的人力、物力、时间等耗费获得较大的成果。
例如，人们说“经济地利用自然资源"。
另-定义则用来统称人类社会生产、消费、交换等活动，及组织这些活动的制度、系统，如工业经济、国民经济、计划经济、市场经济等。
经济一词的这两种定义之间存在着内在的联系。
因为任何经济活动，从个人消费、企业生产到整个国民经济，都必须考虑如何以最少的耗费来达到最大的效益。
在英文中economy一词源于希腊文，原义指家计管理，特别是指家庭收支方面的管理。
持家之本是勤俭节约，economy自然便成了“节俭”的同义词。
这词后来又衍生出“政治经济学’’和“经济学",用来指研究人类社会经济活动的科学。
政治经济学一词最早出现于17世纪。
那时，欧洲的国家在经济活动中的作用日渐显要。
于是,最初在法国，politique被冠于economie而构成“政治经济学”一词，用以指对国家事务的公共管理.在那期间，人们除了研究公共管理的经济政策之外,还研究经济活动本身，诸如生产、消费、交换等的规律。
但所有这些研究都包含在“政治经济学”这一名词之下。
到19世纪中叶，政治经济学的含义受到两方面的批判。
马克思和恩格斯认为，自李嘉图以后，政治经济学已经庸俗化，回避对资本主义经济运动本质的研究,用生产一般来代替对资本主义经济的研究。
认为政治经济学应该是关于资本义生产方式以及和这种生产方式相适应的生产关系和交换关系的理论，同时提出适于各个社会的广义政治经济学.另一种观点则认为“政治经济学”一词令人误解。
主张以“经济学"一词来定义研究经济活动内在规律的理论科学，而把“政治经济学”定义为研究经济政策的应用经济学。
但当时及以后的一些经济学家仍将“经济学”和“政治经济学”视为同义词。
ⅣProduction and Cost☻Production Theory ☻Cost TheoryThe Production Function…shows the relationship betweenquantity of inputs used to make a goodand the quantity of output of that good.Q=f (L，K，N，E)•Q=f (L，K ) Short-run•Q=f (L，K) Long-run•Total Product TP=f (L，K)•Average Product AP=TP/L or AP=TP/K •Marginal ProductIn the production process, marginalproduct of any input is the increase inoutput that arises from an additional unitof that input.MP = (dTP/dL ) or (dTP/ dK)a Production Function: Helen’s cookie factoryQuantity of(cookies per hour)150140130120110100908070605040302010Hungry Helen’s Production FunctionMPTP•The slope of TP curve measures the marginal product of an input.•When the marginal product declines, TP curve becomes flatter(decreasing).Diminishing Marginal Product•…is the property whereby the marginalproduct of an input declines as the quantityof the input increases.•As more and more workers are hired at a firm, each additional worker contributes less and less to production because the firm has a limited amount of equipment.•At the beginning of production process…typical production curve-106.2-5809.625211512.51014151520151512.51010627277777570604525101010910810710610510410310210110MP L AP L TP L L K Short-run<>=00TUMUXX•MU ＞0，TU ↑increasing •MU ＜0，TU ↓decreasing •MU ＝0，TU max00TPMP,APLLTP L & MP L•MP L ----the slope of TP L curve•MP L ＞0，TP L increasingMP L increasing & decreasing•MP L ＜0，TP L decreasing •MP L ＝0，TP L maxAP LMP LTP LAP L & MP L•MP L ＞AP L ，AP L increasing •MP L ＜AP L ，AP L decreasing •MP L ＝AP L ，AP L maxTP L & AP L•AP L ---the slope of segment whichlinks the original and any point on TP L curve•When the segment is just the tangent of TP L curve , MP L ＝AP L ，AP L maxL 2L 1L 3ⅠⅢⅡlong-run Q=f (L，K)•Isoquant curve•Isocost curve•OptimizationFour Properties of Isoquant Curves •Higher isoquant curves are preferred tolower ones.•Isoquant curves do not cross.•Isoquant curves are downward sloping.•Isoquant curves are bowed inward.KQ1Q2CBAD⊿K⊿K⊿L⊿LLLaw of Diminishing Marginal Rate of Technical Substitution•RTSLK =－⊿K/⊿L•It is the rate at which a firm is willing to trade one factor for another.RTS•If ⊿L→0, RTSLK=－dK / dL•C = w·L ＋r·K •K = C/ r －(w/ r)·LWhat the firm can affordThe slope (absolute value)of the isocost lineequals the relative price of the two factors.K LC/wC/ rProducer OptimumBest Combination of Factors•Given quantity, minimize cost •Given cost, maximize quantityKQ1 ABOptimumECLKQ1Q2Q3ABOptimumE CLProducer Optimum occurs…… at the point where the highest isoquant curve and the isocost curve are tangent.•C = w· L＋r· K ; Q=f (L, K)•RTS=w/ rLK•MP/ MP K =w/ rL/ w = MP K / rLAccording to the Law of Supply:•Firms are willing to produce and sell a greater quantity of a good when the price of the good is high.The economic goal of the firmis to maximize profits.Total Revenue, Total Cost, and Profit•Total RevenueThe amount a firm receives forthe sale of its output.•Total CostThe market value of the inputsa firm uses in production.•Profit…is the firm’s TR minus its TC.Costs as Opportunity CostsA firm’s cost of production includes all theopportunity costs of making its output ofgoods and services.Explicit and Implicit Costs •Explicit costs are input costs that require a direct outlay of money by the firm.•Implicit costs are input costs that do not require an outlay of money by the firm.Economic Profit & Accounting Profit π=TR（Q）－TC（Q）•Economists measure a firm’s economic profit as TR minus TC, including both explicit and implicit costs.•Accountants measure the accounting profit as the firm’s TR minus only the firm’s explicit costs.✶When TR exceeds both explicit and implicit costs, the firm earns economic profit.✶Economic profit is smaller than.accounting profit.✶Normal profitTypical Cost Curves•The relationship between the quantity a firm can produce and its costs determines pricing decisions.For many firms, the division of TC between fixed and variable costs depends on the time horizon being considered.•In the short run,some costs are fixed.•In the long run,fixed costs become variable costs.The Various Measures of Cost•Costs of production (TC)may be dividedinto fixed costs and variable costs.costs in the short-runFixed and Variable Costs•Fixed costs are those costs that do not varywith the quantity of output produced.•Variable costs are those costs that do varywith the quantity of output produced.Total Costs•Total Fixed Costs (TFC)•Total Variable Costs (TVC)•STC= TFC+ TVC= r· K ＋w· L (Q)Average Costs•AC can be determined by dividing the firm’s costs by the quantity of output it produces.•AC is the cost of each typical unit of product. ✓Average Total Costs SAC=STC/Q=AFC+ AVC ✓Average Fixed Costs AFC=TFC/Q✓Average Variable Costs AVC =TVC/QMarginal Cost•MC measures the increase in TC that arises from an extra unit of production.SMC = ⊿STC/⊿Q= ⊿TVC/⊿QIf ⊿Q→0, MC = d TC/ d Q= d TVC/ d QCost Curves and Their Shapes •SMC、STC、TVCSMC=⊿STC/⊿Q=⊿TVC/⊿Q=⊿w· L/⊿Q=w/(⊿Q/⊿L)=w/MP L•MC rises with the amount of output producedwhich reflects the property of diminishing MP L .•MP L ---reciprocal “U”-Shaped•MC ---“U”-ShapedTVC 、TFC 、STC●TFC---straight line●SMC----the slope of STC or TVC curveMC ---“U”-ShapedMC＞0，STC and TVC increasing✓MC increasing, STC and TVC increasing at increasing speed ✓MC decreasing, STC and TVC increasing at decreasing speed•AFC 、A VC 、SACA VC=TVC/Q=(w· L)/Q=w/ (Q/L)=w/AP L•AP---reciprocal “U”-ShapedL•AVC and SAC ---“U”-ShapedThe SAC curve is U-shaped.•At very low levels of output SAC is high because FC is spread over only a few units.•SAC declines as output increases.•SAC starts rising because AVC rises substantially.•The bottom of the U-shaped SAC curve occurs at the quantity that minimizes SAC. •This quantity is sometimes called the efficient scale of the firm.Relationship between MC and SAC(AVC)✓Whenever MC is less than SAC, SAC is falling.✓Whenever MC is greater than SAC, SAC is rising. MC crosses SAC at the efficient scale which is the quantity that minimizes SAC.Three Important Properties of Cost Curves•MC eventually rises with the quantity of output.•SAC,A VC curve are U-shaped.•MC curve crosses the A VC and SAC curve at the minimum of A VC and SAC successively .•Because many costs are fixed in the short run but variable in the long run, a firm’s long-run cost curves differ from its short-run cost curves.•LTC = r· K(Q)＋w· L (Q)•LAC = LTC/Q•LMC= dLTC / dQLTC Q 0LMC LTCLMCLAC2013-7-2347STC 1STC 2STC 3TC Q0Q 1Q 2Q 3LTCSAC 1SAC 2SAC 3C 1C 2C 3Q 1Q 2Q 3Q’ 2Q’1O CQEconomies and Diseconomies of Scale •Economies of scale refer to the property whereby LAC falls as the quantity of output increases.•Diseconomies of scale refer to the property whereby LAC rises as the quantity of output increases.•Constant returns of scale refers to the property whereby LAC stays the same as the quantity of output increases.•f（λL，λk）＞λf（L，k）•f（λL，λk）= λf（L，k）•f（λL，λk）＜λf（L，k）。
