sequential bargaining as a noncooperative foundation for walrasian equilibrium allocation are weakly preferred to those obtainable from the initial endowments by means of the given set of net trades these conditions are similar to ones studied by schmeidler and vind 1972 and vind 1978 but here they are thought of as characterizing the set of net trades available in steady state equilibria of market games like those studied by douglas gale 1984 1985 1986a 1986b and 1986c the characterization result is used as a key step in the proof of results like gale s the allocations induced by steady state equilibria are walrasian for the economy given by the constant flow of new agents into the market our approach generalizes the one followed in gale 1986c and allows us to dispense with assumptions made in previous treatments for example gale s 1986a assumption of dispersed characteristics is dropped we also demonstrate that such a result depends on the assumption that agents cannot observe the past behavior of agents with whom they trade

an expository note on individual risk without aggregate uncertainty abstract in economies where agents bear some risk the analysis would often be facilitated by the assumption that the risks are i i d and disappear in the aggregate a formal appeal to the law of large numbers requires the consideration of a sequence of finite economies in an economy with a continuum of agents there are countable families of sets for which it is impossible for a law of large numbers to be valid with countably many agents and a finitely additive measure independence is compatible with the law of large numbers

arbitrage and the flattening effect of large numbers abstract in a model of an exchange economy with a continuum of individuals we show that competitive equilibrium can be regarded as resulting from the elimination of arbitrage opportunities generically the elimination of such opportunities results in a phenomenon we call the flattening effect of large numbers the flattening effect provides a precise meaning to the statement that under perfect competition individuals cannot influence prices they face perfectly elastic demands and supplies the attractive geometry associated with arbitrage and the flattening effect is highlighted in several figures we also link the demonstration of equilibrium through arbitrage with the logic of marginalism journal of economic literature classification number d51

an empirical model of labor supply in a life cycle setting this paper formulates and estimates a structural intertemporal model of labor supply using theoretical characterizations derived from an economic model of lifetime behavior a two step empirical analysis yields estimates of intertemporal and uncompensated substitution effects which provide the information needed to predict the response of hours of work to life cycle wage growth and shifts in the lifetime wage path

bargaining and markets complexity and the competitive outcome abstract rubinstein and wolinsky rev econ stud 57 1990 63 78 consider a simple decentralised market game in which agents meet randomly or voluntarily and bargain over the terms of trade they show that any individually rational price can be sustained as a sequential equilibrium even though the model has a unique competitive outcome here i consider rubinstein and wolinsky s model and show that if complexity costs of implementing strategies enter players preferences together with the standard payoff in the game then every equilibrium is stationary markov and induces the unique competitive price thus i demonstrate that aversion to complexity may provide a justification for the competitive outcome

dynamic matching and bargaining games a general approach this paper presents a new characterization result for competitive allocations in quasilinear economies this result is informed by the analysis of non cooperative dynamic search and bargaining games such games provide models of decentralized markets with trading frictions a central objective of this literature is to investigate how equilibrium outcomes depend on the level of the frictions in particular does the trading outcome become walrasian when frictions become small existing specifications of such games provide divergent answers the characterization result is used to investigate what causes these differences and to generalize insights from the analysis of specific search and bargaining games

a model of the demand for longevity and the value of life extension we specify a demand function for longevity or quantity of life along with corresponding demand functions for indicators of quality of life and a value of health and life extension function we show that the demand for health must be derived in conjunction with that for longevity and the related consumption plan and that all choices depend on initial individual endowments and terminal conditions our comparative dynamics predictions indicate that optimal health and longevity are increasing functions of endowed wealth rather than necessarily current income that improvements in opportunities to produce health can accentuate the differences between endowed health and attained longevity levels and that the value individuals ascribe to their health may be increasing over a good portion of their life cycle we use this model to analyze observed empirical variations in levels and trends of life expectancy and in exposure to health risks across different population groups

the meaning of death some simulations of a model of healthy and unhealthy consumption simulations of a model of healthy and unhealthy consumption are used to investigate the impact of various terminal conditions on life span pathways of health related consumption and health a model in which life span and the death stock of health are fixed is compared to versions in which i the death stock of health is freely chosen ii life span is freely chosen iii both the death stock of health and life span are freely chosen the choice of terminal conditions has a striking impact on optimal plans results are discussed with reference to the existing demand for health literature and illustrate the application of iterative processes to determine optimal life span the role played by the marginal value of health capital in determining optimal plans and the importance of checking the second order conditions for the optimal choice of life span

bargaining in dynamic markets abstract we study non stationary markets in which traders are randomly matched to bargain over the price of a heterogeneous good or the terms of a partnership the economy consists of a continuum of players drawn from a finite set of types players exogenously enter the market over time and exit upon trading at every date matching probabilities for each pair of types are determined by the endogenous distribution of trader types in the market the balance of bargaining power at any stage depends on variations in potential gains from trade the inflows of new traders the structure of agreements at future dates and the induced frequency of trading opportunities we establish that an equilibrium always exists moreover all equilibria that lead to the same evolution of the economy are payoff equivalent however we show that multiple self fulfilling expectations about the trajectory of the economy generating distinct equilibrium dynamics and payoffs may coexist

equilibrium in a market with sequential bargaining this paper considers a market where pairs of agents who are interested in carrying out a transaction are brought together by a stochastic process and upon meeting initiate a bargaining process over the terms of the transaction the basic bargaining problem is treated with the strategic approach the paper derives the steady state equilibrium agreements analyzes their dependence on market conditions such as the relative numbers of agents of different types and discusses their relations with the competitive equilibrium outcome and other results in the search equilibrium literature this paper considers a market that operates in the following way pairs of agents who have mutual interest in carrying out a transaction are brought together by a stochastic process when two agents meet they initiate a bargaining process over the terms of the transaction if two agents reach an agreement a transaction takes place and they leave the market of course the bargaining positions and hence the agreement reached in any particular meeting will be affected by the conditions prevailing in the market these will include the chances that each of the negotiating parties have of meeting other partners in the event that the agreement in the current negotiations is delayed also the expected length of time required to achieve an alternative transaction and the expected behavior of alternative partners the study of such a market mechanism is of interest for two reasons firstly it captures some realistic aspects of the trade in certain specific markets e g asset markets such as housing and some labor markets secondly it contributes to an understanding of the micro mechanisms of price formation and their role in shaping market outcomes in both cases the features studied are largely neglected in the traditional market equilibrium analyses the related literature includes the articles by diamond 4 5 diamond and maskin 6 mortensen 8 9 and zusman and bell 13 these articles consider markets of the type described above in which transactions are concluded at pairwise meetings of agents the major difference between our work and these articles is in the approach to the basic bargaining problem in the cited articles it is assumed that a meeting is concluded with an instantaneous agreement which divides the associated surplus in an arbitrary predetermined way when the surplus is assumed to be divided equally the division rule is in fact nash s axiomatic bargaining solution in contrast the present paper treats the basic bargaining problem with the strategic approach see rubinstein 19 which constitutes an attempt to look into the bargaining black box this approach explicitly models the time dimension of the bargaining process describes in detail the bargaining procedure and justifies the agreement as a perfect equilibrium in

walrasian allocations without price taking behavior abstract consider an exchange economy where agents are arbitragers in that they try to upset allocations imagining plausible beneficial trades with an introspective algorithm each agent constructs an interactive choice set ics i e a set of bundles that he considers achievable through a sequence of plausible trades with other agents we show that walrasian allocations can be characterized as those where each agent chooses optimally from his ics which is always contained in a budget set with differentiability both sets coincide our analysis provides a different behavioral assumption underlying walrasian allocations offers an explanation for the source of competitive prices and connects with the core convergence theorem journal of economic literature classification numbers d00 d51

stochastic cascades credit contagion and large portfolio losses abstract we analyze an interactive model of credit ratings where external shocks spread by a contagious chain reaction to the entire economy counterparty relationships along with discrete adjustments of credit ratings generate a transition mechanism that allows the financial distress of one firm to spill over to its business partners the spread of financial distress constitutes a source of intrinsic risk for large portfolios of credit sensitive securities that cannot be diversified away we provide a characterization of the fluctuations of credit ratings in large economies when adjustments follow a threshold rule and analyze the effects of downgrading cascades on credit portfolios

complexity and competition extensive form market games typically have a large number of noncompetitive equilibria in this paper we argue that the complexity of noncompetitive behavior provides a justification for competitive equilibrium in the sense that if rational agents have an aversion to complexity at the margin then maximizing behavior will result in simple behavioral rules and hence in a competitive outcome for this purpose we use a class of extensive form dynamic matching and bargaining games with a finite number of agents in particular we consider markets with heterogeneous buyers and sellers and deterministic exogenous sequential matching rules although the results can be extended to other matching processes if the complexity costs of implementing strategies enter players preferences lexicographically with the standard payoff then every equilibrium strategy profile induces a competitive outcome

markov equilibria in dynamic matching and bargaining games abstract rubinstein and wolinsky rev econ stud 57 1990 63 show that a simple homogeneous market with exogenous matching has a continuum of non competitive perfect equilibria however the unique markov perfect equilibrium of this model is competitive by contrast in the more general case of heterogeneous markets even the markov property is not enough to guarantee the perfectly competitive outcome we define a market game that allows for heterogeneous values on both sides of the market and exhibit a number of examples of non competitive markov perfect equilibria with and without discounting unlike the homogeneous case these equilibria allow for inefficient trades and for trade at non uniform prices the non competitive equilibrium may be unique

comparative dynamic analysis of the full grossman model the paper applies the method of comparative dynamic analysis to the full grossman model for a particular class of solutions it derives the equations implicitly defining the complete trajectories of the endogenous variables relying on the concept of frisch decision functions the impact of any parametric change on an endogenous variable can be decomposed into a direct and an indirect effect the focus of the paper is on marginal changes in the rate of health capital depreciation it also analyses the impact of either initial financial wealth or the initial stock of health capital while the direction of most effects remains ambiguous in the full model the assumption of a zero consumption benefit of health is sufficient to obtain a definite for any direct or indirect effect

convergence to perfect competition of a dynamic matching and bargaining market with two sided incomplete information and exogenous exit rate abstract consider a decentralized dynamic market with an infinite horizon and incomplete information in which buyers and sellers values for the traded good are private and independently drawn time is discrete each period has length and each unit of time a large number of new buyers and sellers enter the market within a period each buyer is matched with a seller and each seller is matched with zero one or more buyers every seller runs a first price auction with a reservation price and if trade occurs the seller and winning buyer exit with their realized utility traders who fail to trade either continue in the market to be rematched or exit at an exogenous rate we show that in all steady state perfect bayesian equilibria as approaches zero equilibrium prices converge to the walrasian price and realized allocations converge to the competitive allocation

health status and health dynamics in an empirical model of expected longevity expected longevity is an important factor influencing older individuals decisions such as consumption savings purchase of life insurance and annuities claiming of social security benefits and labor supply it has also been shown to be a good predictor of actual longevity which in turn is highly correlated with health status a relatively new literature on health investments under uncertainty which builds upon the seminal work by grossman grossman m 1972 on the concept of health capital and demand for health journal of political economy 80 223 255 has directly linked longevity with characteristics behaviors and decisions by utility maximizing agents our empirical model can be understood within that theoretical framework as estimating a production function of longevity using longitudinal data from the health and retirement study we directly incorporate health dynamics in explaining the variation in expected longevities and compare two alternative measures of health dynamics the self reported health change and the computed health change based on self reports of health status in 38 of the reports in our sample computed health changes are inconsistent with the direct report on health changes over time and another 15 of the sample can suffer from information losses if computed changes are used to assess changes in actual health these potentially serious problems raise doubts regarding the use and interpretation of the computed health changes and even the lagged measures of self reported health as controls for health dynamics in a variety of empirical settings our empirical results controlling for both subjective and objective measures of health status and unobserved heterogeneity in reporting suggest that self reported health changes are a preferred measure of health dynamics

on adaptation and the demand for health the purpose of this paper is to analyse the impacts of adaptation to failing health this is done by integrating adaptation processes in a grossman type of pure consumption model model simulations show that adaptation affects the health variables by lowering the incentives to invest in health as well as smoothing the optimal health stock path over the life cycle whether or not the risk of mortality is an object of choice has important effects when studying adaptation as well as for the joint development of the health variables

retrading in market games when agents are not price takers they typically cannot obtain an efficient real location of resources in one round of trade this paper presents a non cooperative model of imperfect competition where agents can retrade allocations consistent with edgeworth s idea of recontracting we show a there are pareto optimal allocations including competitive equilibrium allocations that can be approximated arbitrarily closely when trade is myopic i e when agents play a static nash equilibrium at every round of retrading b any converging sequence of allocations generated by myopic retrading can be supported along some retrade proof subgame perfect equilibrium path when traders anticipate future rounds of trading

the inheritance of inequality how level is the intergenerational playing field what are the causal mechanisms that underlie the intergenerational transmission of economic status are these mechanisms amenable to public policies in a way that would make the attainment of economic success more fair these are the questions we will try to answer

market clearing and price formation abstract considered here is decentralized exchange of privately owned commodity bundles voluntary transactions take the form of repeated bilateral barters under broad and reasonable hypotheses the resulting process converges to competitive equilibrium price taking behavior is not assumed prices emerge over time they need neither be anticipated nor known at any interim stage