transfers to sustain dynamic core theoretic cooperation in international stock pollutant control international environmental agreements aiming at correcting negative externalities generated by transboundary pollution are difficult to achieve for many reasons important obstacles arise from asymmetry in costs and benefits and instability may occur due to the fact that coalitions of countries may attempt to do better for themselves outside of any proposed agreement in a static context it has already been shown that it is possible to achieve stability in the sense of the core of a co operative game by means of appropriately defined transfers between the countries involved however the transboundary pollution problems that are most important are caused by accumulated pollutants so that a dynamic analysis is required this paper provides a transfer scheme that yields a core property in a dynamic context the possibility of computing such transfers numerically is discussed

buying cooperation in an asymmetric environmental differential game abstract we consider a two player asymmetric differential game of pollution control one player is non vulnerable to pollution or unwilling to consider damages when choosing her production policy in a non cooperative game we characterize the feedback nash equilibrium and the cooperative solution we establish conditions under which the vulnerable player can buy the cooperation of the non vulnerable player to control her emissions we further use the nash bargaining solution to allocate the total cooperative dividend between the two players and propose a time consistent decomposition overtime of the total payoff

trade s dynamic solutions to transboundary pollution abstract this study develops a differential game to examine the effects of trade liberalization on transboundary water pollution water pollution is due to wastewater emissions from countries in a shared waterway along the u s mexico border with available data of pollution abatement costs public health damages and trade benefits noncooperative and cooperative games are examined with changes in trade policy and public health damages results show trade liberalization leads mexico to curtail pollution in both games cooperation and trade liberalization limit emissions from both countries and curtail strategic behavior of the united states from mexico s pollution control efforts in the noncooperative game

making sense of the competitiveness debate the debate over national competitiveness is marked by some basic misperceptions with few exceptions those who use the term have a crude essentially mercantilist view of world trade in which competition among nations is just like competition between corporations not only do the authors and readers of reports on national competitiveness usually not understand comparative advantage they are unaware of the most basic adding up constraints economists however find it hard to believe that seemingly well informed people can really be this naive and assume that there must be more sophisticated ideas lying behind what they say the rationales offered by economists in turn offer false comfort to the would be sophisticates who like the term competitiveness they believe that they have transcended conventional economic theory when the fact is that they have failed to comprehend it in short the actual level of discussion is lower than any of the participants imagines copyright 1996 by oxford university press

trade liberalization and the environment in the pacific basin coordinated approaches to mexican trade and environment policy in this paper we analyze the environmental implications of growth and opening up of trade in mexico based on an empirical economywide model in particular we study how tradeoffs between growth and environmental objectives can be minimized by using targeted policies on pollution emissions in coordination with outward oriented trade strategies most economywide studies of trade and environment linkages rely on effluent intensities associated with output and do not allow for substitution between nonpolluting factors labor and capital and polluting intermediate consumption such as chemicals or energy lee and roland holst by contrast pollution emissions in the present model are linked to using polluting inputs rather than directly to output levels we also embed this analysis in a dynamic framework to take account of exogenous components of factor supply and productivity growth over the twenty year period 1990 to 2010 the analysis is presented in three stages first pollution abatement policies are considered alone and their effects on growth sectoral allocation and trade are evaluated the next step is to consider trade liberalization alone trade distortions in place before the nafta and uruguay round accords are removed progressively over time and results calibrate the expansionary effects of trade liberalization as well as its environmental implications these include win win cases such as in the fertilizer sector as well as intensified environmental degradation arising from the transportation sector in a third and last scenario we combine environmental and trade policies and show how they interact these results indicate that the combination of policies generally can mitigate the undesirable effects of each set of policies alone such as trade induced pollution growth and the real contractionary effects of environmental policy thus it appears that more liberal and outward oriented trade policy can coexist with more rigorous attention to environmental values the trade and environment debate has

the acid rain differential game this paper considers an acid rain differential game countries emit sulphur which is partly transferred to other countries depositions above critical loads ultimately destroy the soil countries face a trade off between the costs of emission reductions and the damage to the soil due to the depletion of the acid buffers because of the transboundary externalities the outcome will depend on whether the countries cooperate or not this paper presents the cooperative outcome and the open loop and markov perfect nash equilibria of the acid rain differential game it will be shown that the depositions always converge to the critical loads but the steady state levels of the buffer stocks differ the theory is used to analyse the acid rain differential game for sulphur between great britain and ireland finally some results are given for the whole of europe

international pollution control cooperative versus noncooperative strategies abstract international pollution control involving two neighboring countries is modeled as a simple two player dynamic game each country produces a good that is consumed by domestic households production of each consumption good results in emissions of pollutants households in each country derive utility from the consumption of the domestically produced good but incur costs through the total stock of pollution stock externality in this setting we characterize cooperative as well as noncooperative pollution control strategies of the governments of the two countries that maximize the discounted stream of net benefits of a representative consumer it turns out that when the governments are restricted to use linear strategies noncooperative behavior results in overall losses for both countries if on the contrary governments use nonlinear markov perfect strategies and the discount rate is small enough a pareto efficient steady state pollution stock can be supported as a differentiable subgame perfect equilibrium thus the emergence of first best solutions cooperative outcomes does not require any institutional arrangements threats retaliation etc but can be brought about through the use of nonlinear markov perfect equilibrium strategies

transboundary pollution in the black sea comparison of institutional arrangements this paper analyses the transboundary pollution between romania and ukraine coastal states along the black sea and studies the welfare consequences of institutional arrangements for controlling this problem to achieve this goal we use a dynamic and strategic framework we compare in terms of total welfare for two countries a first best case with three different institutional arrangements the non cooperative game of countries the uniform emission policy and the constant emission policy as proposed by the black sea commission our findings indicate that the non cooperative game provides a better level of total welfare than the other rules

pigouvian taxation of energy for flow and stock externalities and strategic noncompetitive energy pricing abstract the literature on energy and carbon taxes is by and large concerned about the derivation of globally efficient strategies in contrast this paper considers the dynamic interactions between cartelized energy suppliers and a consumers government that collectively taxes energy carriers for pigouvian motives two different kinds of external costs are associated with energy consumption flow e g acid rain and stock externalities e g global warming the dynamic interactions between a consumers government and a producers cartel are modeled as a differential game with a subgame perfect nash equilibrium in linear and nonlinear markov strategies the major implications are that the nonlinear solutions are pareto inferior to the linear strategies and energy suppliers may preempt energy taxation and thereby may raise the price at front however this effect diminishes over time because the producers price declines while taxes increase

subgame perfect cooperative agreements in a dynamic game of climate change abstract we model climate change as a dynamic game and prove existence of a unique subgame perfect nash equilibrium spne that is also markov perfect we interpret this unique spne as the business as usual bau equilibrium and show that if the countries are not sufficiently symmetric then the familiar trigger strategy equilibria may not be pareto improvements over the bau equilibrium and may even lack efficiency properties we then motivate and introduce a subgame perfect cooperative agreement as an improvement over the bau equilibrium in the sense that every country or coalition of countries is better off in every subgame irrespective of the extent of heterogeneity of the countries we characterize subgame perfect cooperative agreements and identify sufficient conditions for their existence we show that direct or indirect transfers between countries to balance the costs and benefits of controlling climate change are a necessity and not a matter of approach

capacity utilization measures underlying economic theory and an alternative approach measures of industrial capacity utilization hereafter cu have been used extensively in helping to explain changes in the rate of investment labor productivity and inflation the cu measures have also been used to obtain indices of capital in use as distinct from capital stock in place a number of alternative measures of cu are periodically calculated and published the 1980 economic report of the president for example contains three series that by the federal reserve board the u s department of commerce bureau of economic analysis and the wharton school of finance other publicly available series are those prepared by mcgraw hill publishing company the u s department of commerce bureau of the census and rinfret boston associates inc although a host of cu measures is publicly available it is not at all clear how one should interpret changes over time in each measure or variations among them a principal reason underlying these interpretation problems is that the crucial link between underlying economic theory and the constructed measure of cu is weak one way in which this issue has manifested itself in the policy domain over the last five years has been with respect to the uncertain effects of dramatic increases in energy prices on capacity output and on cu each of the cu measures noted above is computed in such a way that explicitly ignores any role for energy prices yet several times during the last decade though growth to apparently high rates of cu had taken place investment and average labor productivity were much lower than expected and the rate of price increase much greater in brief during the last decade the explanatory power of alternative cu measures has dropped sharply some have conjectured that post opec energy price increases may have brought about major changes in the u s economy so that old quantitative relationships between measured cu and investment labor productivity and price inflation may have been altered substantially in order to assess effects of changes in pe on cu a re examination of the notion and measurement of cu is needed based on the framework of the economic theory of the firm that is the focus of this paper

nonlinear strategies in dynamic duopolistic competition with sticky prices abstract we discuss nonlinear strategies in an infinite horizon duopoly game with sticky prices where firms maximize their discounted sum of profit we construct a stationary feedback equilibrium without guessing value functions and feedback strategies that solve the hamilton jacobi equation for this purpose we study the auxiliary equation that is derived from the hamilton jacobi equation we show that the domain of the state space plays an crucial role in characterizing feedback equilibria and discuss several implications of this observation in particular we find that when the upper bound of the state space is not very high previously unknown feedback equilibria emerge

trade transboundary pollution and foreign lobbying in this paper we explore the use of trade policy in addressing transboundary stock pollution problems such as acid rain and water pollution we show that a tariff determined by the current level of accumulated pollution can induce the time path of emissions optimal for the downstream polluted country but if the upstream polluting country can lobby the downstream government to impose lower tariffs distortions brought by corruption and foreign lobbying lead to a rise in the upstream country s social welfare and to a decrease in social welfare in the downstream country thus the usefulness of trade policy as a tool for encouraging cooperation and internalizing transboundary externalities depends critically on the degree of governments susceptibility to foreign political influence

valuation methods and policy making in environmental economics 1 valuation methods and policy making in environmental economics relevance and scope h folmer e van ierland part i the valuation of public goods 2 non market asset prices a comparison of three valuation approaches r c d arge j f shogren 3 valuing public goods in a risky world an experiment p o johansson 4 recreational values pareto optimality and timber supply p o johansson k g lofgren k g maler 5 estimating social benefits of environmental improvements from reduced acid rain deposition a contingent valuation survey s navrud part ii the valuation of health and life 6 benefits of reduced morbidity from air pollution control a survey m dickie s gerking 7 valuing a public good direct and indirect valuation approaches to the measurement of the benefits from air pollution abatement m shechter m kim l golan 8 environmental regulation and the valuation of life interindustry mobility and the market price of safety h w herzog jr a m schlottmann part iii cost benefit analysis 9 disequilibrium cost benefit rules an exposition and extension p o johansson k g lofgren 10 macroeconomic cost benefit analysis of environmental programmes a nentjes part iv aspects of policy making 11 benefit estimation for complex policies a randall j hoehn 12 the acid rain game k g maler index

the externalities problem of transboundary and persistent pollution abstract this paper deals with implementing the efficient allocation of transboundary and persistent pollution in particular we adapt varian s compensation mechanism varian a solution to the problem of externalities when agents are well informed amer econ rev 85 1994 1278 1293 to cover situations in which pollutants extend to neighboring regions and their effects persist over time the main contribution of this paper is the design of a mechanism that implements in subgame perfect equilibrium the efficient pollution levels in this context

renegotiation proof equilibria in repeated prisoners dilemma abstract in this note it is shown that the requirement of weak renegatiation proofness does not eliminate any subgame perfect equilibrium outcome of the repeated prisoner s dilemma specifically it is demonstrated that when players are sufficiently patient any feasible and individually rational outcome can be sustained by means of an equilibrium in which the punishing player always profits by carrying out the punishment

economic growth and greenhouse gas emissions abstract recent empirical research has examined the relationship between certain indicators of environmental degradation and income concluding that in some cases an inverted u shaped relationship which has been called an environmental kuznets curve ekc exists between these variables unfortunately this inverted u shaped relationship does not hold for greenhouse gas emissions one explanation of the absence of ekc like behavior in greenhouse gas emissions is that greenhouse gases are special pollutants that create global not local disutility but the international nature of global warming is not the only reason that prevents de linking greenhouse gas emissions from economic growth the intergenerational nature of the negative impact of greenhouse gas emissions may have also been an important factor preventing the implementation of greenhouse gas abatement measures in the past in this paper we explore the effect that the presence of intergenerational spillovers has on the emissions income relationship we use a numerically calibrated overlapping generations model of climate economy interactions we conclude that 1 the intertemporal responsibility of the regulatory agency 2 the institutional capacity to make intergenerational transfers and 3 the presence of intergenerationally lagged impact of emissions constitute important determinants of the relationship between economic growth and greenhouse gas emissions

investment and technical progress models in which the growth rate is exogenous provide no role for government in determining growth in our model growth is associated with investment through externalities from learning by watching rather than with the level of the capital stock presumption of a technical progress function with first increasing and then decreasing returns leads to multiple steady state growth equilibria there is also an explicit role of government policy in setting tax rates on output it follows that two economies with identical structures and stochastic tax policies may exhibit very different growth paths over sustained periods although the stationary distribution of growth rates is the same given the desirability in principle of subsidizing investment various practical methods are considered copyright 1992 by oxford university press

the quantitative consequences of raising the u s saving rate the authors investigate the consequences of a permanent unphased increase in the u s gross saving rate they find that the sacrifice time the time that elapses until consumption surpasses the value it would have had under the initial saving rate is roughly six years and is insensitive to the percentage increase in the saving rate delta sub s the percentage gain in output at the end of decade the decade gain is roughly 26 of delta sub s while the percentage gain in consumption is roughly 8 of delta sub s the saving rate return the internal rate of return on a permanent increase in the saving rate is roughly 16 and is insensitive to delta sub s copyright 1991 by mit press

city economies and microbusiness growth in developed countries microbusinesses those employing fewer than 10 people and home based businesses have been systematically overlooked in urban economic development thinking this article assesses the influence of city location and being run from the business owner s home on microbusiness growth based on empirical analysis of panel firm level data over a four year period during the uk s long boom the analysis reveals that cities provide benefits to microbusinesses for turnover growth but not for employment growth suggesting that the additional growth induced by cities for microbusinesses may be jobless growth however in the case of microbusinesses run from the owner s home cities facilitate growth into medium sized businesses with 50 staff in conclusion microbusinesses including those run from business owners homes are integral to the evolution and dynamics of urban economies and essential to understanding the nature of growth in cities agglomeration theory needs to say more about how urban agglomeration benefits firms of different types and sizes and small business and self employment research needs to say more about the influence of location in particular cities how businesses use both commercial and residential property are integral to the nature of growth in cities

biosecurity incentives network effects and entry of a rapidly spreading pest abstract protection against pest invasion is a public good yet the nature of private incentives to avoid entry is poorly understood this work shows that due to increasing returns or network effects private actions to avoid entry are strategic complements this means that compulsory action at least by a subset of parties can be an effective policy both heterogeneity in biosecurity costs and the effect of private actions on the extent of the invasion threat are shown to have ambiguous effects on the magnitude of welfare loss due to strategic behavior communicated leadership by some party is preferred to simultaneous moves and it may be best if the party with highest biosecurity costs assumes a leadership role

measuring the environmental consequences of trade policy a nonmarket cge analysis the newly approved gatt trade agreement is likely to focus greater attention on the conflicts between the proliferation of diverse national policies toward environmental quality and the need to maintain competitiveness in world markets virtually all policy evaluations of this conflict have been limited by a significant misspecification in existing models none of the available computable general equilibrium cge models for international trading patterns consistently reflect the effects of environmental resources on consumers preferences the purpose of this paper is to report the first generation of a composite nonmarket and cge model nm cge for the european community the united states japan and a single region for the rest of the world the model incorporates the morbidity and mortality effects of particulates sulfur oxides and nitrogen oxides it uses existing nonmarket valuation estimates freeman with a specification for consumer preferences that allows changes in atmospheric emissions to diffuse in different amounts to

ingredients in the early development of the u s biotechnology industry this paper explores the ingredients that stimulated the development of the biotechnology industry in the us and contrasts conditions with those in europe it examines relationships between established firms and new start ups the financing and managerial environment and the organizational environment whereby firms were able to set up networks of alliances its main findings are that 1 the funding of the medical science research base has been substantially more generous in the u s than europe it is the funding of the science base rather than of the biotechnology industry directly that has provided the foundations for start ups to be created out of the science base 2 it has been easier for u s academics to found start ups close to their research establishment and to retain their academic posts and status as well as be involved in a commercial enterprise in europe the scientific academic and commercial worlds have a wider divide 3 start ups have been concentrated in the therapeutics and agricultural fields with strong scientific research inputs into their commercialization in contrast to other sectors where downstream processing innovations have been more important which have been undertaken in house by the large incumbent companies 4 financing and managerial conditions have been significantly easier in the u s for start ups in terms of access to venture capital specialising in high technology ability to use the stock market to raise capital and access to people able to forge links between scientists and entrepreneurs and to introduce managerial expertise into new companies 5 there has been a greater facility in the u s than in europe for alliances to be formed between incumbent companies and indigenous u s start ups european start ups have not found similar backing from european incumbent companies

a two level dynamic game of carbon emission trading between russia china and annex b countries this paper proposes a computable dynamic game model of the strategic competition between russia and developing countries dcs mainly represented by china on the international market of emission permits created by the kyoto protocol the model uses a formulation of i a demand function for permits from annex b countries and ii marginal abatement costs mac in russia and china provided by two detailed models gemini e3 is a computable general equilibrium model that provides the data to estimate annex b demand for permits and macs in russia poles is a partial equilibrium model that is used to obtain mac curves for china the competitive scenario is compared with a monopoly situation where only russia is allowed to play strategically the impact of allowing dcs to intervene on the international emission trading market is thus assessed

a dynamic game of a transboundary pollutant with asymmetric players abstract modeling transboundary pollutants in a dynamic game framework provides a foundation for analyzing the impact of various policy options the focus of this analysis is on the results of a tax subsidy scheme used to address the transboundary problem of global climate change a nonzero sum dynamic game with asymmetric players is used to evaluate the policy impact of the tax subsidy scheme on the respective player s value functions and strategies as determined by a nash equilibrium feedback solution the asymmetry of the players is reflected in their respective attitudes toward global climate change with one player benefiting from the change and the other losing

the consequences of a one sided externality in a dynamic two agent framework abstract we develop a dynamic model where all agents contribute to a global externality but only those in a specific region suffer from it we model this in a dynamic setting via a two agent non cooperative overlapping generations model and analyze the consequences for economic growth and intertemporal choices we find that multiple steady states may result from this asymmetry in particular if the agent who is affected by the externality has to spend a large share of his income to offset it then he may be stuck in an environmental poverty trap we provide conditions for the existence of and local convergence to the equilibria as well as a condition for the global convergence to the poverty trap while in addition to maintenance expenditures externalities tend to be addressed via studying taxes investment in r d or alike we focus on capital market integration specifically agents in the affected region can open up their capital market to enable capital inflows we investigate whether an open capital market improves or worsens their welfare while we do find that capital market integration eliminates the environmental poverty trap we show that capital market integration is not always in both agents interest in particular we provide conditions under which the agents prefer autarkic or integrated capital markets

the oslo protocol on sulfur reduction the great leap forward the increasing number of international environmental agreements ieas and the fact that under some agreements emissions have been reduced beyond agreed targets are frequently viewed as success stories of international cooperation we argue that success can only be measured if abatement targets under an iea are compared with estimated abatement levels in the absence of a treaty and are evaluated in terms of costs and benefits we analyze the oslo protocol on sulfur reduction showing that this iea is not the great leap forward when compared with the calculated nash equilibrium and the social optimum however we also demonstrate that under the oslo protocol more ambitious targets could not have been realized due to strong free rider incentives

pigouvian taxation in tourism the paper studies the characteristics and the effects of a tax imposed by a local government on the land used to create new tourists accommodations first a dynamic policy game between a monopolist in a tourist area and a local government is considered in each period the former has to decide the size of land undergoing development whereas the latter has to choose the tax to levy on each newly developed area unit linear perfect markov strategies are derived for both the non cooperative and the public monopoly case in equilibrium a public monopoly would develop land more rapidly than a private monopoly furthermore the more the monopolist discounts the future the more the long run use of the natural resource is reduced second the properties of the tax are studied considering an oligopolistic market structure the tax alone does not lead to the socially optimal level of land use however its combined effect with another policy instrument such as a quota induces the optimal level of resource use

existence and uniqueness of equilibrium in a distorted dynamic small open economy abstract we provide a set of sufficient conditions for existence and uniqueness of recursive equilibrium for a class of small open economies with distortion the second welfare theorem is not available in this framework and usual approach for studying optimal neoclassical growth models is also not applicable

embryonic knowledge based clusters and cities the case of biotechnology in scotland the cluster concept has been promoted in recent years as a panacea for economic development both locally and nationally one source of theoretical and empirical ambiguity in the concept is related to the spatial processes underpinning cluster development and to the relationship between cities and clusters in particular this paper examines the case of the biotechnology cluster in scottish cities with particular reference to glasgow and edinburgh the promotion of a biotechnology cluster has become a priority for scotland s economic development strategy because of its potential role in the knowledge driven economy the paper examines the major locational dynamics affecting biotechnology in scotland and interrogates the balance between the major forces driving the development of biotechnology firms in their urban location it concludes that the importance of cities to cluster growth lies mainly in the size and diversity of their labour markets in the presence of key research institutions and public sect

partners forever an empirical study of relational ties in two small firm clusters many researchers take as axiomatic the proposition that economic action in clusters is embedded in dense durable and trust based social networks it is suggested here that the bias towards high trust enduring relations obscures the competitive dynamics of networks even where co operation can be identified drawing attention to the competitive motives underlying the construction of social networks an investigation is made into the duration and brokering of dyadic relations in business owners advice networks the analysis of 668 dyadic ties in a population of 113 small business owners in two textile and clothing clusters in germany reveals considerable variation in the duration of social relations and the likelihood that they were formed through third party brokers many of whom were direct competitors creating more ephemeral links the findings suggest that marketless conceptions of social networks in clusters need to be balanced with a stronger concern for the role of competition in the social embe

regulation via the polluter pays principle we consider the problem of regulating an economy with environmental pollution we examine the distributional impact of the polluter pays pp principle which requires that any agent compensates all other agents for the damages caused by his or her pollution emissions with constant marginal damages we show that regulation via the pp principle leads to the unique welfare distribution that induces non negative individual welfare change and renders each agent responsible for his or her pollution impact we extend both the pp principle and this result to increasing marginal damages due to pollution we also compare the pp principle with the vickrey clark groves scheme

a differential game design of watershed pollution management under ecological compensation criterion abstract the watershed ecological compensation is used as a policy instrument in china in order to reduce water pollution and attain watershed sustainability in this paper we construct a differential game between a local government and a profit maximizing local firm with one competitor in a watershed ecological compensation system then the optimal dynamic strategy is obtained by applying maximum principle finally we investigate the influence of shadow prices on control variables and firm s output in three different cases this study focuses on how to reach a balance between the sustainable development of local economy and the effective protection of water resources from an ecological perspective for the local government as well as on how to maximize the profit of the local firm in an ecological compensation system

optimal control for transboundary pollution under ecological compensation a stochastic differential game approach abstract to account for previously ignored yet widely observed uncertainty in nature s capability to replenish the natural environment in ways that should inform ideal design of ecological compensation ec regimes this study constructs a stochastic differential game sdg model to analyze transboundary pollution control options between a compensating and compensated region equilibrium strategies in the stochastic two player game inform optimal control theory and reveal a welfare distribution mechanism to form the basis of an improved cooperative game contract a case based numerical example serves to verify the theoretical results and supports three key insights first accounting for various random disturbance factors the probabilistic pollutant stock in stackelberg non cooperative game exceeds that of a cooperative game situation second the ec mechanism provides long term effective incentives only when the marginal losses of environmental damage in the compensating region are more than twice that of the compensated region achieving a pareto optimal equilibrium relies upon the attainment of a dynamic allocation ratio derived from the analysis of a robust welfare allocation mechanism third cross region cooperation reliably outperforms stackelberg non cooperation due to either overwhelming incumbent economic interests or high abatement costs this study illuminates the importance of balancing both parties interests within an ec agreement while reducing uncertainty around unobserved environmental factors during ex ante negotiations

international aspects of pollution control pollution is a by product of production is only gradually dissolved by the environment and crosses national borders the market outcome ignores the adverse effects of pollution and thus yields higher levels of output and pollution than would prevail under a supranational social planner which does care about pollution in practice governments often do not cooperate and this leads to outcomes of pollution and production in between the market outcomes and the outcomes under supra national social planning absence of precommitment leads to lower emission charges less cleaning up activities and more pollution appropriate levels of emission charges under the various outcomes are a result of this analysis attention is also paid to investment in clean technology the debate between optimists who believe that higher production is compatible with sound environmental policy and pessimists can be analysed in this way