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1.
Summary. Given a map whose roots are the Nash equilibria of a game, each component of the equilibrium set has an associated index,
defined as the local degree of the map. This note shows that for a two-player game, every map with the same roots induces
the same index. Moreover, this index agrees with the Shapley index constructed from the Lemke-Howson algorithm.
Received: May 30, 1996; revised version June 25, 1996 相似文献
2.
Robert Wilson 《Economic Theory》1998,12(2):433-440
Summary. The sequential equilibrium of an ascending-price auction of a single item is derived explicitly for the case of log-normal
distributions and a multiplicative valuation model comprising both common and private factors, and allowing asymmetries. If
the prior distribution on the common factors is diffuse, or of the form obtained by Bayesian updating from a diffuse prior
distribution, then the equilibrium strategies are log-linear with coefficients obtained by solving a set of linear equations.
A similar construction applies to normal distributions and additive terms in the valuation model. An example illustrates the
predictions derived from the model.
Received: December 11, 1996; revised version: July 15, 1997 相似文献
3.
Summary. We study the least core, the kernel and bargaining sets of coalitional games with a countable set of players. We show that
the least core of a continuous superadditive game with a countable set of players is a non-empty (norm-compact) subset of
the space of all countably additive measures. Then we show that in such games the intersection of the prekernel and the least
core is non-empty. Finally, we show that the Aumann-Maschler and the Mas-Colell bargaining sets contain the set of all countably
additive payoff measures in the prekernel.
Received: June 6, 1996; revised version: March 1, 1997 相似文献
4.
Diana Richards 《Economic Theory》1997,10(1):185-193
Summary. This paper contributes to the recent focus on dynamics in noncooperative games when players use inductive learning. The most
well-known inductive learning rule, Brown’s fictitious play, is known to converge for games, yet many examples exist where fictitious play reasoning fails to converge to a Nash equilibrium. Building on ideas
from chaotic dynamics, this paper develops a geometric conceptualization of instability in games, allowing for a reinterpretation
of existing results and suggesting avenues for new results.
Received: October 27, 1995 revised version May 2, 1996 相似文献
5.
Summary. This paper studies adaptive learning in extensive form games and provides conditions for convergence points of adaptive learning
to be sequential equilibria. Precisely, we present a set of conditions on learning sequences such that an assessment is a
sequential equilibrium if and only if there is a learning sequence fulfilling the conditions, which leads to the assessment.
Received: November 5, 1996; revised version: May 28, 1997 相似文献
6.
Summary. In this note we show that if in the standard Rubinstein model both players are allowed to leave the negotiation after a rejection,
in which case they obtain a payoff of zero, then there exist a continuum of subgame-perfect equilibrium outcomes, including
some which involve significant delay. We also fully characterize the case in which, upon quitting, the players can take an
outside option of positive value.
Received: February 27, 1996; revised version: March 28, 1997 相似文献
7.
Summary. By a cooperative game in coalitional structure or shortly coalitional game we mean the standard cooperative non-transferable
utility game described by a set of payoffs for each coalition being a nonempty subset of the grand coalition of all players.
It is well-known that balancedness is a sufficient condition for the nonemptiness of the core of such a cooperative non-transferable
utility game. In this paper we consider non-transferable utility games in which for any coalition the set of payoffs depends
on a permutation or ordering upon any partition of the coalition into subcoalitions. We call such a game a cooperative game
in permutational structure or shortly permutational game. Doing so we extend the scope of the standard cooperative game theory
in dealing with economic or political problems. Next we define the concept of core for such games. By introducing balancedness
for ordered partitions of coalitions, we prove the nonemptiness of the core of a balanced non-transferable utility permutational
game. Moreover we show that the core of a permutational game coincides with the core of an induced game in coalitional structure,
but that balancedness of the permutational game need not imply balancedness of the corresponding coalitional game. This leads
to a weakening of the conditions for the existence of a nonempty core of a game in coalitional structure, induced by a game
in permutational structure. Furthermore, we refine the concept of core for the class of permutational games. We call this
refinement the balanced-core of the game and show that the balanced-core of a balanced permutational game is a nonempty subset
of the core. The proof of the nonemptiness of the core of a permutational game is based on a new intersection theorem on the
unit simplex, which generalizes the well-known intersection theorem of Shapley.
Received: October 31, 1995; revised version: February 5, 1997 相似文献
8.
Summary. In this paper the alternating offer model with an exogenous risk of breakdown is taken to explicitly model the bargaining process underlying the variable threat game (Nash, Econometrica, 1953). A modified version of the variable threat game without commitment is also analysed within a dynamic context. The limit set of subgame perfect equilibria is characterized in both dynamic versions. The analysis gives rise to different results than in the two standard models. By making additional assumptions the original results can be regained, indicating that these are implicitly present in the standard analysis.Received: August 29, 1995; revised version: November 11, 1996This revised version was published online in February 2005 with corrections to the cover date. 相似文献
9.
Summary. This article characterizes all of the continuous social welfare orderings which satisfy the Weak (resp. Strong) Pareto principle
when utilities are ratio-scale measurable. With Weak Pareto, on both the nonnegative and positive orthants the social welfare
ordering must be representable by a weakly increasing Cobb-Douglas social welfare function while on the whole Euclidean space
the social welfare ordering must be strongly dictatorial. With Strong Pareto, on the positive orthant the social welfare ordering
must be representable by a strictly increasing Cobb-Douglas social welfare function but on the other two domains an impossibility
theorem is obtained.
Received: July 31, 1995; revised version August 7, 1996 相似文献
10.
Summary. This paper derives the set of equilibria for common agency games in which the principals compete in piece rates and lump
sum payments and one principal has incomplete information about the agent's preferences. We show that the uninformed principal's
expected payoff function is discontinuous with respect to the identity of the marginal agent type. This discontinuity is shown
to support an open set of equilibria. For games in which the first-best equilibrium strategies are measurable with respect
to the uninformed principal's information partition, this result implies the existence of an open set of Pareto inefficient
equilibria.
Received: December 5, 1995; revised version August 18, 1996 相似文献
11.
A resolution of N-person prisoners' dilemma 总被引:5,自引:0,他引:5
Ko Nishihara 《Economic Theory》1997,10(3):531-540
Summary. The purpose of this paper is to show that cooperation is possible in N-person prisoners' dilemma if players have incomplete information on the order of their moves. We consider a modified version
of N-person prisoners' dilemma in which players sequentially move in the order determined by Nature, and during the play they
get some information about others. We provide an information partition and a condition of payoffs for which cooperation is
attained in an equilibrium. Further, for the case that full cooperation is not attained, we examine the largest partial cooperation
which is achieved in an equilibrium.
Received: March 5, 1995; revised version August 11, 1996 相似文献
12.
Kin Chung Lo 《Economic Theory》1998,12(1):1-20
Summary. Traditional analysis of auctions assumes that each bidder's beliefs about opponents' valuations are represented by a probability
measure. Motivated by experimental findings such as the Ellsberg Paradox, this paper examines the consequences of relaxing
this assumption in the first and second price sealed bid auctions with independent private values. The multiple priors model
of Gilboa and Schmeidler [Journal of Mathematical Economics, 18 (1989), 141–153] is adopted specifically to represent the bidders' (and the auctioneer's) preferences. The unique equilibrium
bidding strategy in the first price auction is derived. Moreover, under an interesting parametric specialization of the model,
it is shown that the first price auction Pareto dominates the second price auction.
Received: December 15, 1995; revised version: February 19, 1997 相似文献
13.
Ed Nosal 《Economic Theory》1997,10(3):413-435
Summary. When players are unable to write complete state contingent contracts it is shown, within the context of a non-cooperative
contracting-renegotiation game, that the only subgame perfect equilibrium allocations are those that correspond to the set
of first-best allocations. Players are able to implement this set of allocations by signing an initial contract that is subsequently
renegotiated in all states of the world. The contracting-renegotiation problem is complicated in an interesting way by assuming
that the state space is continuous. The issue of the existence of an initial contract, that is subsequently renegotiated to
the set of first-best allocations, must be resolved. Unlike Aghion, Dewatripont and Rey [1994], the results here do not require
nor depend upon the comonotonicity of the objective functions.
Received: January 27, 1995; revised version July 1, 1996 相似文献
14.
Summary. We consider k agents who have different subjective probabilities and are utility maximizers. A planner, who knows the beliefs of the agents,
maximizes the social expected utility, which is increasing and symmetric in the utilities of the agents. She does that by
optimally stopping the flow of information released to the agents. The explicit form of the optimal stopping time is given.
Received: October 23, 1995; revised version: June 25, 1997 相似文献
15.
Licun Xue 《Economic Theory》1998,11(3):603-627
Summary. We analyze strategic social environments where coalitions can form through binding or nonbinding agreements and actions of
a coalition may impose externalities upon the welfare of the rest of the players. We define a solution concept that (1) captures
the perfect foresight of the players that has been overlooked in the literature (e.g., Harsanyi [10] and Chwe [6]) and (2) identifies the coalitions
that are likely to form and the “stable” outcomes that will not be replaced by any coalition of rational (and hence farsighted)
players. The proposed solution concept thereby offers a notion of agreements and coalition formation in complex social environments.
Received: February 12, 1996; revised version: March 3, 1997 相似文献
16.
Summary. In the social learning model of Banerjee [1] and Bikhchandani, Hirshleifer and Welch [2] individuals take actions sequentially
after observing the history of actions taken by the predecessors and an informative private signal. If the state of the world
is changing stochastically over time during the learning process, only temporary informational cascades – situations where
socially valuable information is wasted – can arise. Furthermore, no cascade ever arises when the environment changes in a
sufficiently unpredictable way.
Received: December 5, 1996; revised version: February 11, 1997 相似文献
17.
In-Uck Park 《Economic Theory》1998,11(2):413-426
Summary. In a novel formulation of revealed preference analysis, Green and Osband [8] show that for expected-utility maximizers, acts
partition the state-simplex into linear polyhedral blocks. The question naturally arises whether this characterization distinguishes
expected utility theory from non-expected utility theories. This paper investigates the weighted utility theory of Chew [2]
and shows that the corresponding partition is systematically different from the expected utility theory: the boundaries of
the partition blocks are quadratic rather than linear. This result contains useful empirical contents.
Received: May 15, 1995; revised version: November 22, 1996 相似文献
18.
Julio Dávila 《Economic Theory》1998,12(1):213-223
Summary. It is shown in this note that in an incomplete markets economy with uncountably many states of the world there may be uncountably
many isolated equilibria as well as uncountably many non-isolated equilibria. Moreover, both subsets can be simultaneously
of second category. Therefore, none of the subsets can be considered negligible with respect to the other, neither from a
cardinality point of view nor from a topological one. Unfortunately, this fact prevents from claiming that these economies
may have “typically” determinate equilibria – even though uncountably many of them – as would have been desirable for comparative
statics exercises.
Received: May 19, 1995; revised version: March 24, 1997 相似文献
19.
Summary. We show that when bankruptcy, subject to penalties, is allowed, it is possible to prove the existence of equilibrium in a model with a continuum of states without imposing any assumptions on ex-post endowments.Received: November 20, 1995; revised version: September 16, 1996This revised version was published online in February 2005 with corrections to the cover date. 相似文献
20.
Rafael Tenorio 《Economic Theory》1999,13(1):247-260
Summary. I study a multiple unit auction where symmetric risk-neutral bidders choose prices and quantities endogenously. In the model,
bidders (a) may place non-linear valuations on the auctioned units, and (b) bid for several units at the same price (“lumpy”
bids). I characterize quantity-symmetric and strictly monotone-increasing price equilibria for discriminatory and competitive
auctions, and show that (i) if quantity strategy profiles are equal across auctions revenue- equivalence holds, (ii) expected
revenue is higher if bidders bid for the entire supply rather than for shares of it, and (iii) equilibrium allocations may
fail to be Pareto-optimal.
Received: April 14, 1995; revised version: September 3, 1997 相似文献