on the robustness of equilibrium refinements abstract the philosophy of equilibrium refinements is that the analyst if he knows things about the structure of the game can reject some nash equilibria as unreasonable the word know in the preceding sentence deserves special emphasis if in a fixed game the analyst can reject a particular equilibrium outcome but he cannot do so for games arbitrarily close by then he may have second thoughts about rejecting the outcome we consider several notions of distance between games and we characterize their implications for the robustness of equilibrium refinements

reputation with equal discounting in repeated games with strictly conflicting interests we analyze reputation effects in two player repeated games of strictly conflicting interests in such games player 1 has a commitment action such that a best reply to it gives player 1 the highest individually rational payoff and player 2 the minmax payoff players have equal discount factors with positive probability player 1 is a type who chooses the commitment action after every history we show that player 1 s payoff converges to the maximally feasible payoff when the discount factor converges to one this contrasts with failures of reputation effects for equal discount factors that have been demonstrated in the literature journal of economic literature classification number c71

reputation and impermanent types i consider a version of the chain store game where the incumbent firm s type evolves according to a markov process with two states a tough type who always fights entry and a weak type who prefers to accommodate there exists a minimal level of persistence necessary for the incumbent to be able to sustain any reputation for being tough above that level as the number of markets t increases in equilibrium play alternates between intervals of entry by competitors and intervals of deterrence when t is infinite then regardless of the discount factor there exists a sequential equilibrium in which the incumbent s payoff is bounded below her stackelberg payoff both results are in contrast to the outcome when the incumbent s type is fixed one interpretation is that reputation is not permanent but must be renewed occasionally

uncertainty in the theory of renewable resource markets the natural growth rate of most renewable resource stocks is in part stochastic this paper examines the implications of such ecological uncertainty for competitive equilibrium in a market with property rights we show that stochastic fluctuations add a risk premium to the rate of return required to keep a unit of stock in situ and we examine the effects of fluctuations on resource rent examples are used to show that extraction can increase decrease or be left unchanged as the variance of the fluctuations increases depending on the extent of market self correction regulatory implications are also discussed renewable resource economics has traditionally been concerned with the study of dynamically optimal harvesting policies given a deterministic function for the natural growth of the resource stock issues have included the existence and characteristics of steady state equilibria for the optimally managed resource the need for and design of regulatory policies to prevent over exploitation and conditions under which as a social optimum or otherwise the resource will be exploited to extinction 1 much of this work has been based on the assumption of a fixed and exogenous price for the harvested resource typically resulting in bang bang solutions for the harvesting policy however some recent papers make price endogenous and thereby describe how the extraction rate and the rate of return and asset value of the resource behave in a competitive market with property rights 2

investment demand when economic depreciation is stochastic the neoclassical model of investment by a risk neutral firm is generalized to include uncertainty about the rate of depreciation by replacing the deterministic capital accumulation identity with a stochastic variant ito s stochastic dynamic optimization is used to derive conditions for optimal investment a nondegenerate steady state distribution of the capital stock is shown to exist and is derived for the empirically important case of a normalized quadratic profit function and static price expectations it is demonstrated for this case that uncertainty about the rate of depreciation decreases the expected steady state capital stock and investment

technical change uncertainty and investment the expected investment dynamics of the risk neutral firm is examined in the presence of uncertainty in the future evolution of the real wage and the stock of technical knowledge a model of the adjustment cost firm is developed that is characterized by quasi fixed factor augmenting technical change that is taken exogenously by the firm the effect of wage and technical change uncertainty on investment behavior is assessed using comparative stochastic dynamic analysis

reputation and experimentation in repeated games with two long run players this paper considers reputation effects in a repeated game between two long run players one of whom is relatively patient and may be committed to a fixed strategy which punishes the opponent for increasingly long periods whenever inappropriate actions are taken by following this commitment strategy the more patient player can induce a sufficiently patient opponent to experiment to see whether the commitment strategy is also being followed off the equilibrium path this can guarantee the more patient player in any nash equilibrium a payoff close to the highest feasible payoff consistent with the individual rationality of the other player for an arbitrary degree of patience of the less patient player a weaker result is established the more patient player is guaranteed an average equilibrium payoff close to the static stackelberg payoff this latter result generalizes that of schmidt 1993 who established the same result for the restricted class of games of conflicting interests

reputation and dynamic stackelberg leadership in infinitely repeated games abstract the paper studies a repeated game in which a long run player without discounting faces another long run player with strict discounting the game is perturbed so that there is uncertainty in the patient player s strategy choice she may be a rational player but she may also be one of many irrational types who are committed to various repeated game strategies the rational patient player s equilibrium payoff in this perturbed game is analyzed in particular it is shown that the lower bound on her payoff in the set of extensive form trembling hand perfect equilibria is given by her stackelberg payoff in a dynamics sense journal of economic literature classification numbers c72 d82

unforeseen contingencies and incomplete contracts we scrutinize the conceptual framework commonly used in the incomplete contract literature this literature usually assumes that contractual incompleteness is due to the transaction costs of describing or of even foreseeing the possible states of nature in advance we argue however that such transaction costs need not interfere with optimal contracting i e transaction costs need not be relevant provided that agents can probabilistically forecast their possible future payoffs even if other aspects of the state of the nature cannot be forecast in other words all that is required for optimality is that agents be able to perform dynamic programming an assumption always invoked by the incomplete contract literature the foregoing optimality result holds very generally provided that parties can commit themselves not to renegotiate moreover we point out that renegotiation may be hard to reconcile with a framework that otherwise presumes perfect rationality however even if renegotiation is allowed the result still remains valid provided that parties are risk averse

uncertain climate change and the international policy response abstract the implications of alternative policy responses to uncertain climate change are analyzed within the context of a simple dynamic economic model the analysis emphasizes two sources of uncertainty that surround climate change scientific uncertainty about how greenhouse gas emissions affect the climate and natural climatic variability the analysis also incorporates an economy s ability to mitigate climate changes through emissions reductions as well as its ability to adapt to such changes through adjusting production decisions while the model is very stylized and excludes some broader issues of social optimality and the allocation of rights to resources across generations basic implications of uncertainty in a dynamic world are highlighted that have not been previously discussed these results suggest that analysts will have a difficult time trying to determine whether a certain emissions strategy improves economic efficiency whether the benefits are greater than the costs when uncertainty is explicitly incorporated into the analysis

reputation and perfection in repeated common interest games abstract we consider a wide class of repeated common interest games perturbed with one sided incomplete information one player the informed player might be a commitment type playing the pareto dominant action as discounting which is assumed to be symmetric and the prior probability of the commitment type go to zero it is shown that the informed player can be held close to her minmax payoff even when perfection is imposed on the equilibrium journal of economic literature classification numbers c73 d83

reputation and exogenous private learning abstract short run competitors in the chain store game receive noisy signals of the long run incumbent firm s type the history of signals which in the limit is fully revealing is observable to the competitors but possibly not to the incumbent as long as there is sufficient noise in the signals then in any equilibrium a patient weak incumbent obtains a payoff strictly higher than her minmax payoff

reputation and imperfect information abstract a common observation in the informal literature of economics and elsewhere is that is multistage games players may seek early in the game to acquire a reputation for being tough or benevolent or something else but this phenomenon is not observed in some formal game theoretic analyses of finite games such as selten s finitely repeated chain store game or in the finitely repeated prisoners dilemma we reexamine selten s model adding to it a small amount of imperfect or incomplete information about players payoffs and we find that this addition is sufficient to give rise to the reputation effect that one intuitively expects

reputation in long run relationships we model a long run relationship as an infinitely repeated game played by two equally patient agents in each period the agents play an extensive form stage game of perfect information with either locally non conflicting interests or strictly conflicting interests there is incomplete information about the type of player 1 while player 2 s type is commonly known we show that a sufficiently patient player 1 can leverage player 2 s uncertainty about his type to secure his highest pay off compatible with player 2 s individual rationality in any perfect bayesian equilibrium of the repeated game copyright 2012 oxford university press

a theory of ambiguity credibility and inflation under discretion and asymmetric information this paper develops a positive theory of credibility ambiguity and inflation under discretion and asymmetric information the monetary policymaker maximizes his own politically motivated objective function that is positively related to economic stimulation through monetary surprises and negatively related to monetary growth the relative importance he assigns to each target shifts stochastically through time his current preference trade off is known to him but not to the public when choosing the state contingent path of money growth for the present and the future the policymaker compares the benefits from current stimulation with the costs associated with higher future inflation expectations current monetary growth conveys information to the public about future money growth because there is persistence in the policymaker s objectives although expectations are rational information is imperfect because monetary control procedures are imprecise as a result the public cannot correctly distinguish persistent changes of emphasis on different policy objectives from transitory monetary control errors the public becomes aware of changes gradually by observing past monetary growth credibility is defined in terms of the speed with which the public recognizes changes in the objectives of the policymaker credibility is lower the noisier monetary control and the more stable the objectives of the policymaker looser monetary control and a higher degree of time preference on the part of the policymaker induce him to produce higher and more variable monetary growth when the policymaker is free to determine the accuracy of monetary control he does not always choose the most effective control available in spite of the fact that monetary surprises always have an expected value of zero the reason is that ambiguous control procedures enable the policymaker to generate positive surprises when he cares more than on average about economic stimulation he leaves the inevitable negative surprises for periods in which he cares more about inflation prevention this result provides an explanation for the fed s preference for ambiguity recently documented by goodfriend 1986 the policymaker is more likely to pick more ambiguous control procedures the more uncertain his objectives and the higher his time preference the paper also provides a theoretical underpinning for the well documented crosscountry positive correlation between the level and the variability of inflation

cooperative investments and the value of contracting recent articles have shown that contracts can support the efficient outcome for bilateral trade even in the face of specific investments and incomplete contracting these studies typically considered selfish investments that benefit the investor e g the seller s investment reduces her production costs the authors find very different results for cooperative investments that directly benefit the investor s partner e g the seller s investment improves the buyer s value of the good most importantly if committing not to renegotiate the contract is impossible then contracting has no value i e the parties cannot do better than to abandon contracting altogether in favor of ex post negotiation

ex ante efficient mechanism with private entry costs this paper studies ex ante efficient resource allocation mechanism in an environment where agents endowed with their private values must incur private entry costs to participate due to the nature of this bidimensional screening problem and the difficulty in fully characterizing all implementable endogenous entries the domain of the related social planner s problem that is essential for establishing the existence of efficient mechanism needs to be carefully designed we find that a second price auction among the entrants with a reserve price equal to the seller s valuation is ex ante efficient and any ex ante efficient mechanism must be ex post efficient jel d44 d61 d82

repeated games with long run and short run players this paper studies the set of equilibrium payoffs in repeated games with long and short run players and little discounting because the short run players are unconcerned about the future each equilibrium outcome is constrained to lie on their static reaction best response curves the natural extension of the folk theorem to games of this sort would simply include this constraint in the definitions of the feasible payoffs and minmax values in fact this extension does obtain under the assumption that each player s choice of a mixed strategy for the stage game is publicly observable but in contrast to standard repeated games the set of equilibrium payoffs is different if players can observe only their opponents realized actions

the folk theorem with imperfect public information the authors study repeated games in which players observe a public outcome that imperfectly signals the actions played they provide conditions guaranteeing that any feasible individually rational payoff vector of the stage game can arise as a perfect equilibrium of the repeated game with sufficiently little discounting the central condition requires that there exist action profiles with the property that for any two players no two deviations one by either player give rise to the same probability distribution over public outcomes the results apply to principal agent partnership oligopoly and mechanism design models and to one shot games with transferable utilities copyright 1994 by the econometric society

maintaining a reputation against a long lived opponent we consider a game between a patient player 1 and a nonmyopic but less patient opponent player 2 as usual in reputation models we suppose that the patient player s type is private information and that he may be a commitment type who is locked into playing a particular strategy we investigate the extent to which an uncommitted or normal type of patient player can exploit his less patient opponent s uncertainty to maintain a reputation for playing like a commitment type

ex post renegotiation proof mechanism design we study what kind of equilibria of which mechanisms are ex post renegotiation proof eprp i e robust against the possibility of ex post renegotiation under a variety of renegotiation procedures and which social choice functions are eprp implementable in complete information environments with two agents only budget balanced groves allocations are eprp implementable while with three or more agents all ex post efficient allocations are in environments with independent private values essentially only the budget balanced groves in expectations allocations are eprp implementable while with three or more agents and correlated beliefs all ex post efficient allocations are

investment under uncertainty and dynamic adjustment in the finnish pork industry bykyosti s pietola and robert j myersmay 1998paper prepared for a selected paper session at the annual meeting of the american agriculturaleconomics association salt lake city utah august 1998 this research was financed jointly byagricultural economics research institute in finland the academy of finland and the finnishcultural foundation we also knowledge the michigan agricultural experiment station for itssupport of this research authors are agricultural economist agricultural economics research institute helsinki finland and associate professor department of agricultural economics michigan state university eastlansing copyright 1998 by kyosti s pietola and robert j myers all rights reserved readers may makeverbatim copies of this document for non commercial purposes by any means provided that thiscopyright notice appears on all such copies

adjustment costs uncertainty and the behavior of the firm this paper examines the effects of demand and cost uncertainty on a firm s investment output and pricing decisions but unlike most earlier studies in which demand and cost are simply not known at the time an output or pricing decision is made here i consider uncertainties over future demand and costs it will be seen that the effects of such uncertainties depend critically on the characteristics of the firm s adjustment costs i treat demand uncertainty in a dynamic context by letting the market demand function shift randomly but continuously through time according to a stochastic process this means that today s demand is known exactly but future demand may be larger or smaller and has a variance that increases with the time horizon likewise uncertainty over factor costs is characterized by treating those variables as stochastic processes i combine this characterization of uncertainty with a dynamic model of the firm in which some factor inputs can be adjusted freely in response to stochastic demand changes but other factors are quasi fixed in that adjustment costs are incurred when they are changed in this model the firm s price and output are random processes but we can examine the firm s behavior in expected value terms of interest is whether the presence of uncertainty should cause competitive or monopolistic firms to invest and produce more or less than they would otherwise how the effects of uncertainty are influenced by the presence of risk aversion and how the use of inventories can alter the impact of uncertainty on capacity and sales of course these questions have been addressed by others in the past among the earliest studies of demand uncertainty are those of edwin mills 1959 1962 and samuel karlin and charles carr 1962 mills examined a single period monopolistic firm that sets both output and price and showed that additive demand uncertainty i e the demand function is of the form q q p u where u is a random variable leads to a lower price if marginal cost is constant so that the firm reduces the expected loss from discarding unsold production karlin and carr confirmed for both the static case and the multiperiod case with inventory carryover that additive uncertainty tends to reduce the price and increase the output of a risk neutral firm while multiplicative uncertainty does the opposite other papers have been concerned with the way in which the error term enters the demand function additively multiplicatively or nonlinearly the implications of choosing price ex ante instead of output the implications of risk aversion and the use of inventories for example agnar sandmo 1971 and david baron 1970 showed that a risk averse competitive firm will produce less when the price is a random variable or subject to an additive error term but a riskneutral firm will not alter its production hayne leland 1972 extended these results to a monopolistic firm whose demand can depend in a general way on a random error term for example q q p u and showed that uncertainty reduces the production of a

gambling reputation repeated bargaining with outside options we study the role of incomplete information and outside options in determining bargaining postures and surplus division in repeated bargaining between a long run player and a sequence of short run players the outside option is not only a disagreement point but reveals information privately held by the long run player in equilibrium the uninformed short run players offers do not always respond to changes in reputation and the informed long run player s payoffs are discontinuous the long run player invokes inefficient random outside options repeatedly to build reputation to a level where the subsequent short run players succumb to his extraction of a larger payoff but he also runs the risk of losing reputation and relinquishing bargaining power we investigate equilibrium properties when the discount factor goes to 1 and when the informativeness of outside options diffuses in both cases bargaining outcomes become more inefficient and the limit reputation building probabilities are interior publication abstract

complexity and renegotiation a foundation for incomplete contracts the paper considers a hold up model where only one of n future trading opportunities will prove to be efficient and where ex post renegotiation of the ex ante contract cannot be prevented as the environment becomes more complex n the outcome under any message contingent long term contract converges to that of the incomplete contracting model where trade is contractible ex post but not ex ante when trades are costly to describe both ex ante and ex post the incomplete contracting result is extended to a broader class of environments

reputation and the flow of information in repeated games this paper derives payoff bounds from reputation effects akin to those of fudenberg and levine 1992 for repeated moral hazard games in which a long run player interacts frequently with a population of short run players and the monitoring technology varies with the length of the period of interaction the bounds depend on the monitoring technology through the flow of information a measure of signal informativeness per unit of time based on the relative entropy examples are shown where under complete informatione the set of equilibrium payoffs of the long run player converges as the period length tends to zero to the set of static equilibrium payoffs whereas when the game is perturbed by a small ex ante probability on commitment types reputation effects remain powerful in the frequent interaction limit

reputation and equilibrium characterization in repeated games with conflicting interests a two person game is of conflicting interests if the strategy to which player one would most like to commit herself holds player two down to his minimax payoff suppose there is a positive prior probability that player one is a commitme nt type who will always play this strategy then player one will get a t least her commitment payoff in any nash equilibrium of the repeated game if her discount factor approaches one this result is robust against further perturbations of the informational structure and in striking contrast to the message of the folk theorem for games with incomplete information copyright 1993 by the econometric society

predation reputation and entry deterrence abstract economists often argue that predatory practices are irrational since there exist cheaper or more certain means to gain or maintain a monopoly our gametheoretic equilibrium analysis suggests that if a firm is threatened by several potential entrants then predation may be rational against early entrants even if it is costly when viewed in isolation because it yields a reputation which deters other entrants asymmetric information plays a crucial role in our analysis since it provides the rationale for entrants to base their expectations of the firm s future behavior on its past actions the analysis also suggests methods to treat general reputational phenomena

principles of stochastic dynamic optimization in resource management the continuous time case abstract a wide range of problems in economics agriculture and natural resource management have been analyzed using continuous time optimal control models where the state variables change over time in a stochastic manner using a firm level investment model and a model of environmental degradation this paper provides a concise introduction to continuous time stochastic control techniques the process used to derive the differential of a stochastic process is stressed and in turn is used to explain ito s lemma bellman s equation the hamilton jacobi equation the maximum principle and the expected dynamics of choice variables a basic extension of the dynamic duality literature is also provided where the hamilton jacobi equation is used to derive a stochastic and dynamic analogue of hotelling s lemma

technical change and irreversible investment under risk abstract a stochastic dynamic model was constructed to analyze investment decisions of an individual farmer under risk in the presence of irreversibilities embedded technical change and indivisible capital an analytical solution was obtained and its local behavior studied by numerical methods optimal investment is obtained by regulating the difference between the desired and actual capital stocks between two barriers that define an inaction interval while the desired capital drifts between the barriers no action is taken if the desired capital touches the upper barrier the farmer invests pushing the average efficiency of the actual capital stock up this in turn raises the desired capital even higher and contracts the inaction interval if these effects are strong enough the farmer will invest again until the potential gains of the technological package are exhausted if the desired capital falls enough the farmer disinvests pushing down the average productivity and expanding the inaction interval disinvestment continues until it stops either because the inaction interval becomes so wide that it is no longer optimal to disinvest or because the actual capital stock is so small that it is no longer profitable to produce

is more information always better a case in credit markets this paper studies the impact of behavioral and non behavioral information contained in consumer credit reports on the credit market a repeated game of incomplete information between a borrower and a sequence of lenders is considered lenders beliefs regarding the borrower s type depend on the borrower s historical loan performance and other informative signals it is established that for low beliefs strategic defaults occur in equilibrium as the borrower defaults on his loans despite having the ability to repay them further as the ancillary signals become increasingly informative of the borrower s type the range of beliefs over which strategic defaults occur expands this increase in strategic defaults highlights an unintended negative effect of allowing informative signals to influence beliefs on the upside the informative signals allow lenders to learn the borrower s type more quickly

renegotiation proof implementation and time preferences this paper explores how the requirement that the implementation of contracts be renegotiation proof affects the set of contracts that can be implemented in a seller buyer scenario in which the information regarding the agents valuations is nonverifiable this paper explicitly adds a time dimension to an implementa tion problem and introduces a natural criterion of renegotiation proofness for the case of time consuming renegotiation the main insight gained is that the addition of the time dimension enlarges significantly the set of contracts that can be implemented in a renegotiation proof manner jel c70 d23 this paper explores how the requirement that the implementation of contracts be renegotiation proof affects the set of con tracts that can be implemented in a seller buyer scenario in which the informa tion regarding the agents valuations is non verifiable the paper s main contributions are that first it explicitly adds a time di mension to an implementation problem and second it introduces a natural criterion of renegotiation proofness for the case of time consuming renegotiation for concreteness the discussion will be conducted in the context of the following example there are two agents a seller and a buyer who sign a contract for the sale of one unit in the future their valuations for the unit denoted by s and b respectively are not known when they sign the contract they become known to both parties after the contract is signed and before it is imple mented thus when it comes to implement ing the contract the parties information is complete but it is assumed to be nonverifi able i e not observable to third parties such as a court 1 when they sign the con tract the parties want to specify for any possible realization of the valuations s b whether or not there will be trade and the price p s b at which it will take place the contract describes the procedure that will be followed after the valuations are real ized the purpose of this procedure is to make sure that the original intentions of the parties are indeed carried out the idea is that the steps laid out in the contract are independent of s b and hence are en forceable by a third party or by a social convention in game theoretic terms a contract specifies a game form that imple ments the function p in the sense that for all s and b p s b is the resulting game s unique subgame perfect equilibrium out come in the context of this scenario we shall investigate the set of price functions p s b that can be so implemented by a contract and examine how this set is affected by the requirement that the contract be renegotia

merging reputation and repeated games with incomplete information we relate and unify several results that appeared in the following domains merging of probabilities perturbed games and reputation phenomena and repeated games with incomplete information journal of economic literature classification numbers c72 d83

information acquisition and reputation dynamics we study dynamic incentives and behaviour in markets with costly discovery of past transactions in our model a sequence of short lived customers interact over time with a single long lived firm that privately knows its type good or opportunistic customers must pay to observe the firm s past behaviour we characterize the equilibrium structure that features accumulation consumption and restoration of reputation the opportunistic firm deliberately builds its reputation up to a point where the maximum periods of information acquired by customers do not reveal past opportunistic behaviour and exploits the customers who most trust the firm copyright 2011 oxford university press

partially verifiable information and mechanism design in a principal agent model with adverse selection we study the implementation of social choice functions when the agent s message space is a correspondence which depends on this true characteristic we characterize such correspondence for which the revelation principle is valid returns must not contradict easily observable elements of the taxpayer s lifestyle in this paper we present a model of two person organizations in which these considerations are important we ask whether the restrictions on fallacious statements inherent in the system are sufficient to achieve the goals of the organization we show that the optimal way of eliciting the agent s response may not be to establish incentives for truthtelling in all instances in our model there is one player the agent who observes the state of the economic system another player the principal takes an action based on the information presented to him by the agent this class of models is often referred to as the principal agent problem in the extensive and growing literature on this problem it has always been assumed that the agent could lie to the principal and therefore that he had to be properly motivated to act at least partially in the principal s interest our formal way of modelling the partial verifiability of information is to introduce the restriction that the agent s responses must lie in a set m o that varies with the true state 0 it is assumed that this set always admits the possibility of responding with the true state the way in which the allowable response set varies with the true state is known to the principal in other respects we retain the usual principal agent formalization in particular the principal is the stackelberg leader in this game he can commit himself to choose a collective action as a function of the message transmitted by the agent whether the variation of the message space with the true observation is purely technological or whether it is induced by the severity of potential actions of the principal

the mirrlees approach to mechanism design with renegotiation with applications to hold up and risk sharing the paper studies the implementation problem first analyzed by maskin and moore 1999 in which two agents observe an unverifiable state of nature and may renegotiate inefficient outcomes following play of the mechanism we develop a first order approach to characterizing the set of implementable utility mappings in this problem paralleling mirrlees s 1971 first order analysis of standard mechanism design problems we use this characterization to study optimal contracting in hold up and risk sharing models in particular we examine when the contracting parties can optimally restrict attention to simple contracts such as noncontingent contracts and option contracts where only one agent sends a message

technical change and applications of dynamic duality to agriculture comment the literature on dynamic duality relationships for infinite horizon control problems has grown considerably benveniste and scheinkman chambers and lopez cooper and mclaren epstein epstein and denny mclaren and cooper given adjustment cost models of the firm with static price expectations similar to epstein recent studies have estimated systems of dynamic factor demands in agriculture howard and shumway 1988 howard and shumway 1987 taylor and monson vasavada and ball vasavada and chambers based on alternative or nonexistent assumptions about technology expectations time is often included as an exogenous variable to reflect technical change while vasavada and chambers correctly point out that alternative expectations mechanisms are essentially ad hoc a chosen expectations framework affects the basic structure of the theoretical model which in turn has implications for the technical change component in the dynamic factor demands the purpose of this comment is to explore problems with the approaches used in the literature to incorporate technical change into empirical dynamic factor demand models some simple alternatives are also discussed because the hamilton

reputation and equilibrium selection in games with a patient player a single long run player plays a simultaneous move stage game against a sequence of opponents who play only once but observe all previous play let the stackelberg strategy be the pure strategy to which the long run player would most like to commit himself if there is positive prior probability that the long run player will always play the stackelberg strategy then his payoff in any nash equilibrium exceeds a bound that converges to the stackelberg payoff as his discount factor approaches one when the stage game is not simultaneous move this result must be modified to account for the possibility that distinct strategies of the long run player are observationally equivalent

reputation in the long run with imperfect monitoring abstract we study an infinitely repeated game where two players with equal discount factors play a simultaneous move stage game player one monitors the stage game actions of player two imperfectly while player two monitors the pure stage game actions of player one perfectly player one s type is private information and he may be a commitment type drawn from a countable set of commitment types who is locked into playing a particular strategy under a full support assumption on the monitoring structure we prove a reputation result for stage games with a strong stackelberg action if there is positive probability that player one is a particular type whose commitment payoff is equal to player one s highest payoff consistent with the players individual rationality then a patient player one secures this type s commitment payoff in any bayes nash equilibrium of the repeated game in contrast if the type s commitment payoff is strictly less than player one s highest payoff consistent with the players individual rationality then the worst perfect bayesian equilibrium payoff for a patient player one is equal to his minimax payoff

maintaining a reputation when strategies are imperfectly observed this paper studies reputation effects in games with a single long run player whose choice of stage game strategy is imperfectly observed by his opponents we obtain lower and upper bounds on the long run player s payoff in any nash equilibrium of the game if the long run player s stage game strategy is statistically identified by the observed outcomes then for generic payoffs the upper and lower bounds both converge as the discount factor tends to 1 to the long run player s stackelberg payoff which is the most he could obtain by publicly committing himself to any strategy

dynamic decisions under risk application of ito stochastic control in agriculture in agricultural economics most studies of dynamic decisions under risk have been empirical with less emphasis on theory in finance resource economics and general economics however ito stochastic control is popular for theoretical work optimal decisions can be characterized using the powerful ito stochastic calculus this paper describes the assumptions and methods of ito control constructs a dynamic model of agricultural decisions under risk and illustrates with four examples

the value of commitment with imperfect observability and private information the idea that commitment is valuable plays a key role in many economic models however bagwell 1995 has shown that commitment may have no value if there is even a slight noise in the observation of the leader s action thus casting doubt on the notion that commitment has strategic value here i reconsider the commitment story in a model where the leader s action is imperfectly observed and the leader has private information and i examine how it is affected by uncertainty about the leader s type and by the observation noise

mechanism design with renegotiation and costly messages in one interpretation of the mechanism design problem the agents in volved are designing a mechanism for themselves rather than having it im posed on them by an outside planner the mechanism may for example be a contract or a constitution in that case they will presumably choose a mecha nism that will deliver a pareto efficient outcome in equilibrium suppose how ever that play of the mechanism results in an out of equilibrium outcome and that this outcome is pareto inefficient then unless they have been able some how to commit to this mechanism the agents can be expected to tear up the contract and negotiate a new pareto efficient outcome in the two agent case this possibility of renegotiation limits the set of social choice rules that can

a programming model with stochastic technology and prices the case of australian agriculture risk associated with stochastic input output coefficients and prices is modeled in a programming specification based upon mean variance analysis and chance constrained programming the algorithm which exploits the features of minos a commercially available computer program is developed and applied to australian agriculture convergence of the algorithm is discussed with the data used the thirty runs of this problem achieved a fast convergence with no more than five cycles the model was used to derive supply response functions of export commodities of australian agriculture the relevant information was generated via parametric variations of prices selected according to a suitable experimental design