This paper studies how to form an efficient coalition—a group of people. More specifically, we compare two mechanisms for forming a coalition by running a laboratory experiment and reveal which mechanism leads to higher social surplus. In one setting, we invite the subjects to join a meeting simultaneously, so they cannot know the other subjects’ decisions. In the other setting, we ask them sequentially, which allows each subject to know his or her predecessor’s choice. Those who decide to join the meeting form a coalition and earn payoffs according to their actions and individual preferences. As a result, we obtain the following findings. First, the sequential mechanism induces higher social surplus than the simultaneous mechanism. Second, most subjects make choices consistent with the subgame-perfect Nash equilibrium in the sequential setting and choose the dominant strategy in the simultaneous setting, when a dominant strategy exists. Finally, when the subjects need to look further ahead to make a theoretically rational choice, they are more likely to fail to choose rationally.

<title>Abstract</title>We present axiomatic characterizations of the <italic>proportional division value</italic> for TU-games, which distributes the worth of the grand coalition in proportion to the stand-alone worths of the players. First, a new proportionality principle, called <italic>proportional-balanced treatment</italic>, is introduced by strengthening Shapley’s symmetry axiom, which states that if two players make the same contribution to any nonempty coalition, then they receive the amounts in proportion to their stand-alone worths. We characterize the family of values satisfying efficiency, weak linearity, and proportional-balanced treatment. We also show that this family is incompatible with the dummy player property. However, we show that the proportional division value is the unique value in this family that satisfies the <italic>dummifying player property</italic>. Second, we propose appropriate <italic>monotonicity</italic> axioms, and obtain axiomatizations of the proportional division value without both weak linearity and the dummifying player property. Third, from the perspective of a variable player set, we show that the proportional division value is the only one that satisfies <italic>proportional standardness</italic> and <italic>projection consistency</italic>. Finally, we provide a characterization of proportional standardness.

<title>Abstract</title>This paper introduces a model to analyze individual externalities and the associated negotiation problem, which has been largely neglected in the game theoretic literature. Following an axiomatic perspective, we propose a solution, as a payoff sharing scheme, called the balanced threat agreement, for such problems. It highlights an agent’s potential influences on all agents by threatening to enter or quit. We further study the solution by investigating its consistency. We also offer a discussion on the related stability issue.

Many countries have implemented an energy labeling system that displays the energy savings performance of buildings. However, previous studies have reported mixed findings on the effectiveness of this system.This study is undertaken in Japan to assess whether energy labels are effective and validate the significance of the label design. We use an online survey to determine the effects of energy labels on target consumers. We choose two energy label designs: one with a stairs rating form design and the second with a rating scale of the energy efficiency. Adopting a within-subjects method, each respondent shown both designs and asked to evaluate the energy-saving level based on the labels. Cross-tabulation confirms the positive effects of labeling on energy-savings levels, which are amplified by increasing the level of the reference point. The highest insulation performance level in Japan complies with a law enacted back in 1993; the results show that greater effects can be realized by increasing the level of the reference point.A logistic regression analysis shows that energy labels with the stairs rating have a negative influence, while labels with a rating scale are preferred based on ease of understanding by the respondents. This suggests that energy labels that offer a rating scale can contribute to facilitating energy savings, although there are problems with the comprehension of the gradation colors which need to be further examined. These results can act as a guideline towards optimal designs of the upcoming task of modifying the energy labeling system in Japan.

Asymmetric information has explained the existence of a bubble in extant theoretical models. This study experimentally analyzes traders' choices with and without asymmetric information based on the riding-bubble model. We show that traders tend to hold a bubble asset for longer, thereby expanding the bubble in a market with symmetric, rather than asymmetric, information. However, when traders are more experienced, the size of the bubble decreases, in which case bubbles do not arise with symmetric information. By contrast, the size of the bubble is stable in a market with asymmetric information. (C) 2019 The Authors. Published by Elsevier B.V.

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We develop a novel model of price-fee competition in bilateral oligopoly markets with non-expandable infrastructures and costly transportation. The model captures a variety of real market situations and it is the continuous quantity version of the assignment game with indivisible goods on a fixed network. We define and characterize stable market outcomes. Buyers exclusively trade with the supplier with whom they achieve maximal bilateral joint welfare at prices equal to marginal costs. Maximal fees and the suppliers’ market power are restricted by the buyers’ credible threats to switch suppliers. Maximal fees also arise from a negotiation model that extends price competition to price-fee competition. Competition in both prices and fees necessarily emerges. It improves welfare compared to price competition, but buyers will not be better off. The minimal infrastructure achieving maximal aggregate welfare differs from the minimal network that protects buyers most.

While the European Central Bank experienced severe overbidding in the conduct of its fixed-rate operations, the Bank of Japan has not. Theoretical analyses argue that the reason is that the currently accommodative financial environment in Japan has made bidders' objective functions locally satiated. We conduct an experiment with fixed-rate operations and find that, even as participants' initial demands are large, an explosion of bids does not arise if the objective functions are sufficiently satiated. We also estimate the bid functions from the experimental data and a simple calibration based on the functions indicates that fixed-rate operations are vulnerable to overbidding even when some degree of satiation is preserved.

By conducting a laboratory experiment, we investigate how consumers' purchasing behavior for certified forest coffee is affected by consumers' interest in environmental issues, the provision of information, and product labels. We contribute to the literature in the following three ways. First, we conduct a randomized controlled trial (RCT) to control biases due to endogeneity. Second, we utilize eye-trackers to examine how different product labels result in different visual attention. The combination of an RCT and eye-tracking techniques is new in the literature on purchasing behavior for environmentally friendly products. Third, our experiment measures participants' purchasing behavior that incurs actual costs rather than examining their willingness-to-pay (WTP) based on hypothetical questions. We find that concerns regarding environmental issues do not promote purchases of certified forest coffee. Information about certification programs does not have any effect on purchasing certified forest coffee unless information is provided to prior purchasers of certified forest coffee. By contrast, illustrations of forests on certified forest coffee labels attract participants' visual attention and further stimulate actual purchases of certified forest coffee, suggesting that a 1-second increase in visual attention increases the likelihood of purchasing certified forest coffee by 22 percentage points.

We introduce a new axiom, which we term the balanced contributions property for equal contributors. This axiom is defined by restricting the requirement of the balanced contributions property (Myerson, 1980) to two players whose contributions to the grand coalition are the same. We prove that this axiom, together with efficiency and weak covariance, characterizes a new class of solutions, termed the r-egalitarian Shapley values. This class subsumes many variants of the Shapley value, e.g., the egalitarian Shapley values and the discounted Shapley values. Our characterization provides a new axiomatic foundation for analyzing variants of the Shapley value in a unified manner.

We identify the necessary and sufficient condition under which the Shapley value coincides with the prenucleolus for general TU games. For 0-normalized 3-person games, the coincidence holds if and only if the game is symmetric or satisfies the PS property (Kar et al., 2009). We also identify the necessary and sufficient coincidence condition in the following allocation problems: the airport games (Littlechild and Owen, 1973), the bidder collusion games (Graham et al., 1990) and the polluted river games (Ni and Wang, 2007). The coincidence between the Shapley value and the CIS and ENSC values is discussed as well. (C) 2017 Elsevier B.V. All rights reserved.

The purpose of this study is to provide a comprehensive characterization of linear solutions to cooperative games by using monotonicity. A monotonicity axiom states an increase in certain parameters of a game as a hypothesis and states an increase in a player's payoff as a conclusion. We focus on various parameters of a game and introduce new axioms. Combined with previous results, we prove that efficiency, symmetry and a monotonicity axiom characterize (i) four linear solutions in the literature, namely, the Shapley value, the equal division value, the CIS value and the ENSC value, and (ii) a class of solutions obtained by taking a convex combination of the above solutions. Our methodological contribution is to provide a new linear algebraic approach for characterizing solutions by monotonicity. Using a new basis of the linear space of TU games, we identify a class of games in which a solution that satisfies monotonicity is linear. Our approach provides some intuition for why monotonicity implies linearity.

In this paper we introduce a new consistency condition and provide characterizations for several solution concepts in TU cooperative game theory. Our new consistency condition, which we call the random reduction consistency, requires the consistency of payoff vectors assigned by a solution concept when one of the players is removed with some probability. We show that the random reduction consistency and other standard properties characterize the Weber set, the convex hull of the marginal contribution vectors. Another salient feature of random reduction consistency is that, by slightly changing its definition, we can characterize the core and the anti-core in a parallel manner. Our result enables us to compare the difference between the three solution concepts from the viewpoint of consistency.

A (point-valued) solution for cooperative games with transferable utility, or simply TU-games, assigns a payoff vector to every TU-game. In this paper we discuss two classes of equal surplus sharing solutions. The first class consists of all convex combinations of the equal division solution (which allocates the worth of the 'grand coalition' consisting of all players equally over all players) and the center-of-gravity of the imputation-set value (which first assigns every player its singleton worth and then allocates the remainder of the worth of the grand coalition, N, equally over all players). The second class is the dual class consisting of all convex combinations of the equal division solution and the egalitarian non-separable contribution value (which first assigns every player its contribution to the 'grand coalition' and then allocates the remainder equally over all players). We provide characterizations of the two classes of solutions using either population solidarity or a reduced game consistency in addition to other standard properties.

We hypothesize that if people are motivated by a particular social preference, then choosing in accordance with this preference will lead to an identifiable pattern of eye movements. We track eye movements while subjects make choices in simple three-person distribution experiments. We characterize each choice in terms of three different types of social preferences: efficiency, maxi-min, and envy. For the characterization, we use either the choice data or the eye movement data. The evidence indicates that distributional choices are broadly consistent with the choice rule implied by eye movements. In other words, what subjects appear to be interested in when you look at their choices corresponds to what they appear to be interested in when you look at their eye movements. This correspondence lends credibility to the behavioral relevance of social preferences models. Copyright (c) 2015 John Wiley & Sons, Ltd.

The purpose of this paper is to introduce a new basis of the set of all TU games. Shapley (1953) introduced the unanimity game in which cooperation of all players in a given coalition yields payoff. We introduce the commander game in which only one player in a given coalition yields payoff. The set of the commander games forms a basis and has two properties. First, when we express a game by a linear combination of the basis, the coefficients related to singletons coincide with the Shapley value. Second, the basis induces the null space of the Shapley value. (C) 2016 Elsevier B.V. All rights reserved.

In this paper we introduce discounting in the bidding mechanism of P,rez-Castrillo and Wettstein (J Econ Theory 100:274-294, 2001) who implemented the Shapley value for cooperative transferable utility games. This modification of the mechanism yields the corresponding discounted Shapley value as the payoff distribution in every subgame perfect equilibrium. The class of discounted Shapley values contains the Shapley value and equal division solution as its extreme cases. Interestingly, we obtain axiomatizations of each solution in this class by generalizing the null player property (of the Shapley value) and nullifying player property (of the equal division solution) to the so-called -reducing player property.

We report empirical results related to trust and trustworthiness based on a representative web survey carried out in March 2011 in Japan. Although it initially was intended as a pilot, our survey is unique and unrepeatable because the massive Tohoku earthquake that hit Japan in spring 2011 occurred during the data-collection process and created a natural experiment. Apart from exploring changes originated by the disaster, the novelty of our approach lies in using a multipurpose questionnaire assembled by researchers with diverse interests from different academic areas that allows for exploring political and other social correlates of the economic concepts of trust and trustworthiness as measured by the game-theoretical trust game.

This study investigates two centralized punishment institutions for a linear public goods game. These institutions require a certain contribution level and sanction under-contributing players. The two differ in who, among those who do not meet this requirement, receive sanctions. In one institution, all violators are sanctioned, and in the other, only the worst violator(s) is sanctioned. Theoretically, the public goods game of the latter institution yields contributions equal to or greater than that of the former institution with the same requirement and sanction level. The results of an experiment support this theoretical prediction. However, there is a discrepancy between the theory and laboratory observations in that the institution with the theoretically optimal requirement did not yield the highest profit. (C) 2014 Elsevier Inc. All rights reserved.

Two keyword auction mechanisms, the Generalized Second-Price auction (GSP) and the Vickrey-Clarke-Groves mechanism (VCG), were compared theoretically and experimentally. The former is widely used in practice; the latter is not, but it has a dominant strategy equilibrium where all participants bid their true values. In the theoretical investigation, by applying the locally envy-free Nash equilibrium to the VCG, we found that the allocations are efficient and that upper and lower bounds of the auctioneer's revenue coincide in the two mechanisms. A laboratory experiment, in which the revenues and efficiencies were similar in both mechanisms, supported this result.

One of the main issues in economic allocation problems is the trade-off between marginalism and egalitarianism. In the context of cooperative games this trade-off can be framed as one of choosing to allocate according to the Shapley value or the equal division solution. In this paper we provide three different characterizations of egalitarian Shapley values being convex combinations of the Shapley value and the equal division solution. First, from the perspective of a variable player set, we show that all these solutions satisfy the same reduced game consistency. Second, on a fixed player set, we characterize this class of solutions using monotonicity properties. Finally, towards a strategic foundation, we provide a non-cooperative implementation for these solutions which only differ in the probability of breakdown at a certain stage of the game. These characterizations discover fundamental differences as well as intriguing connections between marginalism and egalitarianism. © 2011 The Author(s).

The coalition formation problem in an economy with externalities can be adequately modeled by using games in partition function form (PFF games), proposed by Thrall and Lucas. If we suppose that forming the grand coalition generates the largest total surplus, a central question is how to allocate the worth of the grand coalition to each player, i.e., how to find an adequate solution concept, taking into account the whole process of coalition formation. We propose in this paper the original concepts of scenario-value, process-value and coalition formation value, which represent the average contribution of players in a scenario (a particular sequence of coalitions within a given coalition formation process), in a process (a sequence of partitions of the society), and in the whole (all processes being taken into account), respectively. We give also two axiomatizations of our coalition formation value. (C) 2012 Elsevier B.V. All rights reserved.

Sanctioning increases cooperation in public goods games, but not indiscriminately under all conditions and in all societies, and the mechanisms by which sanctioning exercises its impact on behavior are yet to be studied in detail. We show experimentally that in the presence of sanctioning, our experimental subjects adjust their behavior in order to avoid being a free rider. They do this not only in the STANDARD sanctions treatment, where they directly experience any sanctions assigned to them, but also in our main treatment, the SECRET sanctions treatment, where no information on sanctions received is available until the end of the experiment. We observe no such free riding avoidance in the treatment without sanctioning. The mere knowledge that sanctions might be assigned increases cooperation among the members of our subject pool; subjects expect that non-strategic sanctioning occurs against the free riders. Moreover, these expectations are correct as we observe a similar pattern and extent of sanctioning in both treatments. We propose that sanctioning in itself is a social norm and may be culturally dependent, as suggested in the literature. (C) 2011 Elsevier Inc. All rights reserved.

A situation, in which a finite set of players can obtain certain payoffs by cooperation can be described by a cooperative game with transferable utility, or simply a TU-game. A (point-valued) solution for TU-games assigns a payoff distribution to every TU-game. In this article we discuss a class of equal surplus sharing solutions consisting of all convex combinations of the CIS-value, the ENSC-value and the equal division solution. We provide several characterizations of this class of solutions on variable and fixed player set. Specifications of several properties characterize specific solutions in this class.

in this paper, we examine the uniqueness of a reduced game in an axiomatic characterization of the core of transferable utility (TU) games in terms of consistency. Tadenuma [10] establishes that the core is the only solution satisfying non-emptiness, individual rationality, and consistency with respect to a natural reduced game due to Moulin [6]. However, the core satisfies consistency with respect to many other reduced games, including unnatural ones. Then we ask whether there are other reduced games that can be used to characterize the core based on the same three axioms. The answer is no: the Moulin reduced game is the only reduced game such that the core is characterized by the three axioms, since for any other reduced game, there is a solution that satisfies the three axioms, but it differs from the core. Many other unnatural reduced games cannot be used to characterize the core based on the three axioms. Funaki [4] provides another axiomatization of the core: the core is the only solution satisfying non-emptiness, Pareto optimality, sub-grand rationality, and consistency with respect to a simple reduced game similar to a so-called subgame. We show that the simple reduced game is the only reduced game that call be used to characterize the core by the four axioms.

In this paper we consider a model of an economy with a common pool resource. Under decreasing returns to scale, it is well-known that no Nash equilibrium attains Pareto efficiency. We examine whether it is possible to achieve Pareto efficiency and avoid the tragedy of the commons through cooperation among players. For that purpose, we use the notion of a game in partition function form. Whether or not the core exists depends crucially on the expectations of each coalition regarding the coalition formation of the outsiders. If each coalition has pessimistic expectations, then the core always exists, while if it has optimistic expectations, the core may be empty.

The egalitarian non-individual contribution (ENIC-)value represents the equal division of the surplus of the total profits, given that each player is already allocated some kind of a yet unspecified individual contribution. Four particular versions, the CIS-, ENSC-, ENPAC-, ENBC-values, are also considered by choosing the individual worth, the separable contribution, the pairwise-averaged contribution and the Banzhaf contribution as the notion of individual contribution. Axiomatic characterizations of the ENIC-value in general and the four particular ENIC valves are provided on the class of cooperative games with a fixed player set as well as a variable player set. The latter axiomatization involves a consistency axiom in terms of reduced games.

The paper introduces a new solution concept for transferable utility games called the Egalitarian Non-Pairwise-Averaged Contribution (ENPAC-) value. This solution arises from the egalitarian division of the surplus of the overall profits after each participant is conceded to gel his pairwise-averaged contribution. Four interpretations of the ENPAC-value are presented. The second part of the paper provides sufficient conditions on the transferable utility game to guarantee that the ENPAC-value coincides with the well known solution called prenucleolus. The main conditions require that the largest excesses al the ENPAC-value are attained at the (n - 2)-person coalitions, whereas the excesses of (n - 2)-person coalitions at the ENPAC-value do not differ.

In this paper we characterize a value, called a marginalistic value, for monotonic set games, which can be considered to be the analog of the Shapley value for TU-games. For this characterization we use a modification of the strong monotonicity axiom of Young, but the proof is rather different from his.

For each cooperative n-person game nu and each h is an element of{1, 2,..., n}, let nu(h) be the average worth of coalitions of size h and nu(h)(i) the average worth of coalitions of size h which do not contain player i is an element of N. The paper introduces the notion of a proportional average worth game (or PAW-game), i.e., the zero-normalized game nu for which there exist numbers c(h) is an element of R such that nu(h) - nu(h)(i) = c(h) (nu(n-1) - nu(n-1)(i)) for all h is an element of {2, 3,..., n - 1}, and i is an element of N. The notion of average worth is used to prove a formula for the Shapley value of a PAW-game. It is shown that the Shapley value, the value representing the center of the imputation set, the egalitarian nonseparable contribution value and the egalitarian non-average contribution value of a PAW-game are collinear. The class of PAW-games contains strictly the class of k-coalitional games possessing the collinearity property discussed by Driessen and Funaki (1991). Finally, it is illustrated that the unanimity games and the landlord games are PAW-games.

The first part is the study of several conditions which are sufficient for the coincidence of the prenucleolus concept and the egalitarian nonseparable contribution (ENSC-) method. The main sufficient condition for the coincidence involved requires that the maximal excesses at the ENSC-solution are determined by the (n - 1)-person coalitions in the n-person game. The second part is the study of both a new type of games, the so-called k-coalitional n-person games, and the interrelationship between solutions on the class of those games. The main results state that the Sharpley value of a k-coalitional n-person game can be written as a convex or affine combination of the ENSC-solution and the centre of the imputation set.