共查询到20条相似文献,搜索用时 46 毫秒
1.
Sylvain Béal 《Theory and Decision》2010,69(2):183-204
We study the finitely repeated prisoner’s dilemma in which the players are restricted to choosing strategies which are implementable
by a machine with a bound on its complexity. One player has to use a finite automaton while the other player has to use a
finite perceptron. Some examples illustrate that the sets of strategies which are induced by these two types of machines are
different and not ordered by set inclusion. Repeated game payoffs are evaluated according to the limit of means. The main
result establishes that a cooperation at almost all stages of the game is an equilibrium outcome if the complexity of the
machines the players may use is limited enough and if the length T of the repeated game is sufficiently large. This result persists when more than T states are allowed in the player’s automaton. We further consider a variant of the model in which the two players are restricted
to choosing strategies which are implementable by perceptrons and prove that the players can cooperate at most of the stages
provided that the complexity of their perceptrons is sufficiently reduced. 相似文献
2.
A path scheme for a game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path. A path scheme is called population monotonic if a player’s payoff does not decrease as the path coalition grows. In this study, we focus on Shapley path schemes of simple
games in which for every path coalition the Shapley value of the associated subgame provides the allocation at hand. Obviously,
each Shapley path scheme of a game is population monotonic if and only if the Shapley allocation scheme of the game is population
monotonic in the sense of Sprumont (Games Econ Behav 2:378–394, 1990). We prove that a simple game allows for population monotonic
Shapley path schemes if and only if the game is balanced. Moreover, the Shapley path scheme of a specific path is population
monotonic if and only if the first winning coalition that is formed along the path contains every minimal winning coalition.
We also show that each Shapley path scheme of a simple game is population monotonic if and only if the set of veto players
of the game is a winning coalition. Extensions of these results to other efficient probabilistic values are discussed. 相似文献
3.
In the Divide-the-Dollar (DD) game, two players simultaneously make demands to divide a dollar. Each player receives his demand
if the sum of the demands does not exceed one, a payoff of zero otherwise. Note that, in the latter case, both parties are
punished severely. A major setback of DD is that each division of the dollar is a Nash equilibrium outcome. Observe that,
when the sum of the two demands x and y exceeds one, it is as if Player 1's demand x (or his offer (1−x) to Player 2) suggests
that Player 2 agrees to λx < 1 times his demand y so that Player 1's demand and Player 2's modified demand add up to exactly one; similarly, Player
2's demand y (or his offer (1−y) to Player 1) suggests that Player 1 agrees to λyx so that λyx+y = 1. Considering this fact, we change DD's payoff assignment rule when the sum of the demands exceeds one; here in this
case, each player's payoff becomes his demand times his λ; i.e., each player has to make the sacrifice that he asks his opponent
to make. We show that this modified version of DD has an iterated strict dominant strategy equilibrium in which each player
makes the egalitarian demand 1/2. We also provide a natural N-person generalization of this procedure.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
4.
We study ultimatum and dictator variants of the generosity game. In this game, the first mover chooses the amount of money
to be distributed between the players within a given interval, knowing that her own share is fixed. Thus, the first mover
is not confronted with the typical trade-off between her own and the other’s payoff. For each variant of the game, we study
three treatments that vary the range of potential pie sizes so as to assess the influence of these changes on the first movers’
generosity. We find that removing the trade-off inspires significant generosity, which is not always affected by the second
mover’s veto power. Moreover, the manipulation of the choice set indicates that choices are influenced by the available alternatives. 相似文献
5.
Two-sided intergenerational moral hazard occurs (i) if the parent’s decision to purchase long-term care (LTC) coverage undermines the child’s incentive to exert effort because
the insurance protects the bequest from the cost of nursing home care, and (ii) when the parent purchases less LTC coverage, relying on child’s effort to keep him out of the nursing home. However, a “net”
moral hazard effect obtains only if the two players’ responses to exogenous shocks fail to neutralize each other, entailing
a negative relationship between child’s effort and parental LTC coverage. We focus on outcomes out of equilibrium, interpreting
them as a break in the relationship resulting in no informal care provided and hence high probability nursing home admission.
Changes in the parent’s initial wealth, LTC subsidy received, and child’s expected inheritance are shown to induce “net” moral
hazard, in contradistinction to changes in child’s opportunity cost and share in the bequest. 相似文献
6.
Choosers as extension axioms 总被引:2,自引:1,他引:1
We consider the extension of a (strict) preference over a set to its power set. Elements of the power set are non-resolute outcomes. The final outcome is determined by an “(external) chooser” which is a resolute choice function. The individual whose preference is under consideration confronts a set of resolute choice functions which reflects the possible behaviors of the chooser. Every such set naturally induces an extension axiom (i.e., a rule that determines how an individual with a given preference over alternatives is required to rank certain sets). Our model allows to revisit various extension axioms of the literature. Interestingly, the Gärdenfors (1976) and Kelly (1977) principles are singled-out as the only two extension axioms compatible with the non-resolute outcome interpretation. 相似文献
7.
In certain judgmental situations where a “correct” decision is presumed to exist, optimal decision making requires evaluation
of the decision-makers’ capabilities and the selection of the appropriate aggregation rule. The major and so far unresolved
difficulty is the former necessity. This article presents the optimal aggregation rule that simultaneously satisfies these
two interdependent necessary requirements. In our setting, some record of the voters’ past decisions is available, but the
correct decisions are not known. We observe that any arbitrary evaluation of the decision-makers’ capabilities as probabilities
yields some optimal aggregation rule that, in turn, yields a maximum-likelihood estimation of decisional skills. Thus, a skill-evaluation equilibrium can be defined as an evaluation of decisional skills that yields itself as a maximum-likelihood estimation of decisional
skills. We show that such equilibrium exists and offer a procedure for finding one. The obtained equilibrium is locally optimal
and is shown empirically to generally be globally optimal in terms of the correctness of the resulting collective decisions.
Interestingly, under minimally competent (almost symmetric) skill distributions that allow unskilled decision makers, the
optimal rule considerably outperforms the common simple majority rule (SMR). Furthermore, a sufficient record of past decisions
ensures that the collective probability of making a correct decision converges to 1, as opposed to accuracy of about 0.7 under
SMR. Our proposed optimal voting procedure relaxes the fundamental (and sometimes unrealistic) assumptions in Condorcet’s
celebrated theorem and its extensions, such as sufficiently high decision-making quality, skill homogeneity or existence of
a sufficiently large group of decision makers. 相似文献
8.
Expected Utility Consistent Extensions of Preferences 总被引:1,自引:1,他引:0
We consider the problem of extending a (complete) order over a set to its power set. The extension axioms we consider generate
orderings over sets according to their expected utilities induced by some assignment of utilities over alternatives and probability
distributions over sets. The model we propose gives a general and unified exposition of expected utility consistent extensions
whilst it allows to emphasize various subtleties, the effects of which seem to be underestimated – particularly in the literature
on strategy-proof social choice correspondences.
相似文献
9.
This paper proposes and justifies a natural way to weaken the concept of covering relation defined on a finite tournament. Various weak covering relations, calledk-covering relations, are introduced. To eachk-covering relation corresponds a strong uncovered set containing all nonk-covered outcomes. It is proved that those strong uncovered sets may be empty. Moreover, the set of all tournaments having an empty strong uncovered set is characterized within two rather large classes of tournaments. Finally, we offer a complete study of the cases where the directed graph defined by ak-covering relation coincides with the initial tournament. 相似文献
10.
On Loss Aversion in Bimatrix Games 总被引:1,自引:0,他引:1
In this article three different types of loss aversion equilibria in bimatrix games are studied. Loss aversion equilibria
are Nash equilibria of games where players are loss averse and where the reference points—points below which they consider
payoffs to be losses—are endogenous to the equilibrium calculation. The first type is the fixed point loss aversion equilibrium,
introduced in Shalev (2000; Int. J. Game Theory 29(2):269) under the name of ‘myopic loss aversion equilibrium.’ There, the
players’ reference points depend on the beliefs about their opponents’ strategies. The second type, the maximin loss aversion
equilibrium, differs from the fixed point loss aversion equilibrium in that the reference points are only based on the carriers of the strategies, not on the exact probabilities. In the third type, the safety level loss aversion equilibrium, the reference
points depend on the values of the own payoff matrices. Finally, a comparative statics analysis is carried out of all three
equilibrium concepts in 2 × 2 bimatrix games. It is established when a player benefits from his opponent falsely believing
that he is loss averse. 相似文献
11.
Ilia Tsetlin 《Theory and Decision》2006,61(1):51-62
Designing a mechanism that provides a direct incentive for an individual to report her utility function over several alternatives
is a difficult task. A framework for such mechanism design is the following: an individual (a decision maker) is faced with
an optimization problem (e.g., maximization of expected utility), and a mechanism designer observes the decision maker’s action.
The mechanism does reveal the individual’s utility truthfully if the mechanism designer, having observed the decision maker’s
action, infers the decision maker’s utilities over several alternatives. This paper studies an example of such a mechanism
and discusses its application to the problem of optimal social choice. Under certain simplifying assumptions about individuals’
utility functions and about how voters choose their voting strategies, this mechanism selects the alternative that maximizes
Harsanyi’s social utility function and is Pareto-efficient. 相似文献
12.
We deal with the ranking problem of the nodes in a directed graph. The bilateral relationships specified by a directed graph
may reflect the outcomes of a sport competition, the mutual reference structure between websites, or a group preference structure
over alternatives. We introduce a class of scoring methods for directed graphs, indexed by a single nonnegative parameter
α. This parameter reflects the internal slackening of a node within an underlying iterative process. The class of so-called
internal slackening scoring methods, denoted by λ
α
, consists of the limits of these processes. It is seen that λ0 extends the invariant scoring method, while λ
∞
extends the fair bets scoring method. Method λ1 corresponds with the existing λ-scoring method of Borm et al. (Ann Oper Res 109(1):61–75, 2002) and can be seen as a compromise between λ0 and λ
∞
. In particular, an explicit proportionality relation between λ
α
and λ1 is derived. Moreover, the internal slackening scoring methods are applied to the setting of social choice situations where
they give rise to a class of social choice correspondences that refine both the Top cycle correspondence and the Uncovered
set correspondence. 相似文献
13.
A characterization of the maximin rule in the context of voting 总被引:1,自引:0,他引:1
In a voting context, when the preferences of voters are described by linear orderings over a finite set of alternatives, the
Maximin rule orders the alternatives according to their minimal rank in the voters’ preferences. It is equivalent to the Fallback
bargaining process described by Brams and Kilgour (Group Decision and Negotiation 10:287–316, 2001). This article proposes
a characterization of the Maximin rule as a social welfare function (SWF) based upon five conditions: Neutrality, Duplication,
Unanimity, Top Invariance, and Weak Separability. In a similar way, we obtain a characterization for the Maximax SWF by using
Bottom Invariance instead of Top Invariance. Then, these results are compared to the axiomatic characterizations of two famous
scoring rules, the Plurality rule and the Antiplurality rule. 相似文献
14.
15.
In the context of indivisible public objects problems (e.g., candidate selection or qualification) with “separable” preferences,
unanimity rule accepts each object if and only if the object is in everyone’s top set. We establish two axiomatizations of
unanimity rule. The main axiom is resource monotonicity, saying that resource increase should affect all agents in the same direction. This axiom is considered in combination with
simple Pareto (there is no Pareto improvement by addition or subtraction of a single object), independence of irrelevant alternatives, and either path independence or strategy-proofness. 相似文献
16.
We present a new method of social choice. The result of our method coincides with that of majority voting when it does not produce an intransitivity among the alternatives under consideration. When majority voting would produce an intransitivity, our method orders the alternatives in the same way as the transitive constituency would whom the committee members are most likely to represent. Analysis of the application of our method to three alternatives shows that (a) the resulting order depends only on the committee members' votes between pairs of alternatives (b) the resulting order is less in conflict with Sen's Property than the orders provided by other schemes (c) when majority voting provides an intransitivity, the hypothesis that, in fact, the committee's constituency is as we assume it to be is almost as likely as the hypothesis that it precisely mirrors the committee. 相似文献
17.
We discuss the privatization schemes of Chile and Argentina following a review of three alternatives to privatization. Our major conclusions are as follows: (1) the Chilean scheme has performed very well during much of the past 15 years, but it is not yet clear what will happen during an extended period of economic stagnation and declining financial markets; (2) for many countries it would make more sense to reform existing public pension schemes than to replace them with privatized schemes, at least until one has a better idea how privatized schemes perform in adverse financial environments; (3) privatized schemes have important distributional effects that deserve more attention. 相似文献
18.
Hagen Lindstädt 《Theory and Decision》2007,62(4):335-353
Sometimes we believe that others receive harmful information. However, Marschak’s value of information framework always assigns
non-negative value under expected utility: it starts from the decision maker’s beliefs – and one can never anticipate information’s
harmfulness for oneself. The impact of decision makers’ capabilities to process information and of their expectations remains
hidden behind the individual and subjective perspective Marschak’s framework assumes. By introducing a second decision maker
as a point of reference, this paper introduces a way for evaluating others’ information from a cross-individual, imperfect
expectations perspective for agents maximising expected utility. We define the cross-value of information that can become negative – then the information is “harmful” from a cross-individual perspective – and we define (mutual) cost of limited information processing capabilities and imperfect expectations as an opportunity cost from this same point of reference. The simple relationship between these two expected utility-based
concepts and Marschak’s framework is shown, and we discuss evaluating short-term reactions of stock market prices to new information
as an important domain of valuing others’ information.
相似文献
19.
Ranking finite subsets of a given set X of elements is the formal object of analysis in this article. This problem has found a wide range of economic interpretations
in the literature. The focus of the article is on the family of rankings that are additively representable. Existing characterizations
are too complex and hard to grasp in decisional contexts. Furthermore, Fishburn (1996), Journal of Mathematical Psychology
40, 64–77 showed that the number of sufficient and necessary conditions that are needed to characterize such a family has
no upper bound as the cardinality of X increases. In turn, this article proposes a way to overcome these difficulties and allows for the characterization of a meaningful
(sub)family of additively representable rankings of sets by means of a few simple axioms. Pattanaik and Xu’s (1990), Recherches
Economiques de Louvain 56, 383–390) characterization of the cardinality-based rule will be derived from our main result, and other new rules that stem from our general proposal are discussed and characterized
in even simpler terms. In particular, we analyze restricted-cardinality based rules, where the set of “focal” elements is
not given ex-ante; but brought out by the axioms.
相似文献
20.
Robert Holzmann 《International social security review》1991,44(1-2):75-93
In all former centrally planned economies, the question of how to restructure old-age income provisions and open the way to non-governmental, complementary pension schemes is being posed. This paper deals with four main areas of that problem. First, the various objectives of public and complementary schemes are discussed. The paper argues that without a broad consensus among the major interested parties there is a considerable danger that envisaged objectives will not be achieved. The second section reviews the main forms of complementary pension scheme and discusses the central characteristics of occupational and personal schemes. The third section addresses two critical policy areas: the kind of regulations that may be required in order to enforce the social and economic objectives; and the likely social and economic implications. On the basis of experience in OECD countries and the specific situation in countries in transition, the final section offers some tentative conclusions for Czechoslovakia, the main one being that during the initial phase of economic transition preference should be given to a simple defined contribution plan. Such a complementary scheme would be consistent with the lack of developed financial markets and the privatization plan of the government and require neither a great number of highly trained accountants and actuaries nor the comprehensive set of regulations a defined benefit plan is likely to dictate. 相似文献