Journal of Game Theory
p-ISSN: 2325-0046 e-ISSN: 2325-0054
2012; 1(5): 38-42
doi: 10.5923/j.jgt.20120105.03
Prakash Chandra1, K. C. Sharma2
1Deptt. of Applied Science & Humanities, Dronacharya College of Engineering, Gurgaon, India
2Deptt. of Mathematics and Computer Science, MSJ Govt. College, Bharatpur, Rajasthan, India
Correspondence to: Prakash Chandra, Deptt. of Applied Science & Humanities, Dronacharya College of Engineering, Gurgaon, India.
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Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved.
In this paper, two groups use the commons as a resource with its near-sightedness and far-sightedness. We study the game with majority of the group and unanimity of the group in its decision making. And we look into the game with the individuals’ utility in making use of the commons with near-sightedness and farsightedness in infinitely repeated game. SPE exists for nearsightedness which tends to destroy the commons in near large period of the game but farsightedness makes safe and useful for infinite period of the survivility of the humanity.
Keywords: Tragedy of the Commons, Repeated Game, Utility, SPE
Cite this paper: Prakash Chandra, K. C. Sharma, "Non Negative Benefits of the Commons in Infinitely Repeated Game", Journal of Game Theory, Vol. 1 No. 5, 2012, pp. 38-42. doi: 10.5923/j.jgt.20120105.03.
Utility of the groups A and B are–
. The society can sustain on the commons, making it in use properly. Let normalize the total population of the society
. If we allowed the optimal exploitation (when the population of the groups is increasing by
), then the size of population be
, and
are opportunity cost for group A and B. when we consider over exploitation on the given opportunity cost, then we can calculate the degree of over exploitation
where
are independent. The degree of over exploitation
In positive
, there be three sections of the feasible payoff region, below we have shown graphical representation of the feasible payoff region. Utility function can be presented
,
which is directly dependent on the payoff from the use of commons in each period. At ground reality, we human have finite year in making use of the commons but we are considering this use for infinite period, having in mind that player will change but intuition of non-negative use of commons remain as it for infinite period (having the aspect of future generations survivility). No group want to destroy the commons (surviving of the groups depend on the use of common) but want to use the commons in such a way – utility difference be close to zero for each group in each period (otherwise collusion between groups for the making use of the commons will take place which can destroy the commons for ever or there may be effect not to use of the commons for a long period of time).
But the sustainability of the commons works or come into reality if their utility to the groups near equal. Inequality of utility in making use of the commons may be the cause of the heavy destruction of the commons or stop the use commons for long period of time which may be reverse reason to finish the users due its missing. In some of the situations of the better or perfect making use of the commons demand the natural player which have no payoff in use of the commons but play the crucial role in the successful use of the commons in infinite period. Proposition 1: For static condition of the two groups, SPE exists if and only if the limit of the utility interval set of group A belong to the utility interval set of group B for each periods in infinitely repeated game. Here we are considering the static condition with the group’s population (there is increasing or decreasing element in the group membership). Neighborhood of
is
where
and neighborhood of
is
where
.
is the limit points of L and H.
,
. There exist a SPE for the making use of commons, whereas we see the limit point of utility interval set of one group belong to the other which show close interrelationship between them to hold equilibrium. In other words we can say –it breaks the thought of dissatisfaction in making use of commons in each period, it works like a spirit of continuity between the groups![]() | Figure 1. ![]() |
approaches to
at each period in use of the commons when
.As we have shown utility function of the groups at each period of time. If
or
at real line and
is the midpoint of utility of the groups then for the group A, neighborhood of the utility θ1, touches θ at least, hold the equilibrium in the making use of the commons in spite of their payoff differences due to the size of the groups which shows as per their need, they are making use of the commons but utility differences are negligible or in the neighborhood of each other. For the group A on the payoff at period t is
which is not always generating fix utility but interval of utility- minimum utility and maximum utility which is min
max
, we can present in interval as
. And For the group B on the payoff at period t is
which is not always generating fix utility but interval of utility- minimum utility and maximum utility which is min
max
, we can present in interval as
where
.Example:-Satellites Occupy in the Orbital Space (Global Commons)-Let the cardinality of the countries in group A and B are
and
and total the capacity of the satellite to be placed in the orbit is N. If total possible launched satellite be
,where maximum level from A-group and B-group is
and
respectively,
. It is the game of complete information (each player know how much satellite can be launched now or empty space to the possible number of satellites), where each group decision to launch an extra satellite can destroy all the system in the orbit which be the cause of heavy loss to both the player groups. Therefore each group player cannot make any decision without permission from the other group player. It means that the decision of the launching satellite be unanimously taken with awareness towards each other. This cooperation between the groups holds due to their farsightedness and welfarism towards humanityProposition 3: If group A and group B have farsightedness and nearsightedness respectively then limit point of utility set of A does not belong to utility set of B when
.For all this 

, utility difference is high due to their vision in making use of the commons which is for group A, is farsightedness and for group B, is nearsightedness. Where nearsightedness imposes to maximize the payoff verses utility high as much as possible in each current period of use the commons without having the thought to save for the future which directly imposes the destruction of the commons. Group B play rationally in to each period. Whereas farsighted vision of the group player A use the commons as per the requirement, having the aspect with the commons to save it and to make use in each period of the coming future without harming. Intersection of the neighborhood of the utility of the group A and utility interval of the group B is null. SPE does not exist which means that the use of the commons soon might be destroyed due to one of the group’s nearsightedness. Therefore there is need to play central role by third player (nature) who does not have any incentive from the commons which look into the survivility of both group in future with the commons. Or this player make the decision for each group, how much each group can use the commons with making possibility to survive today with future aspect ( fix amount use in each period) and coming future with survivility of the next generations. Third player (punishment cell) punish also on the each single extra unit of the commons in each period of the game. Proposition 4: If both groups A and B have nearsightedness then SPE exist for finite periods. The use of commons for future (after finite period of the play) be no more. Nearsightedness imposes the player to maximize the benefits in each periods of the play without having the future aspect of making possible use of the commons. Each group have the limit point of its utility in the others utility interval upto finite period of the play. There exist SPE of the game in that period but having SPE of the game in that period is not guarantee to have SPE in the next period with same efficiency for the player groups .It implies the destruction of commons (Degree of over exploitation is high or close to one or more than one as finite time period increases) and they will not be able to survive in near future because of not having the proper quantity to use from the commons.Proposition 5: If both groups A and B have farsightedness then SPE exist for infinite periods when
.Inclination towards farsightedness of the both groups is a boon for the society where it inclined the welfarism of the society and not interested to maximize their personal payoffs. They have belief to long survivility of the humanity for making use of the commons. Intersection of the neighborhood of the utility of the group A and utility interval of the group B is not null for each condition of the group
and for each periods of the play. There exists a SPE in such each period of the infinitely repeated game.
individual agents have non-observable action
and private (non-monetary) cost
, where
: strictly convex, differentiable and increasing and
. Let 
,
. A joint monetary outcome of the agents,
, where x: strictly increasing, concave and differential and
share of the outcome
. Let the preference function of agent I is
, agents’ initial endowments of money are finite and normalized to be zero. Non-cooperative game with payoffs
has a NE
, which satisfies the condition for Pareto optimality.
is NE
. Pareto optimality
from sharing rules
such that we have budget-balancing
. To reach efficient NE, sharing rule differentiable does not allow. Individual agent i can impose nearsightedness in use of the commons which is rational decision for an individual agent of the society. They are noncooperative to maximize their utility. If they look into the sustainability, it apply-farsightedness and it impose them to come to make all decisions with cooperation of each other.