Pub Date : 2025-12-06DOI: 10.1016/j.mathsocsci.2025.102491
Doron Klunover
We consider a lottery contest between n risk-neutral symmetric players, who compete for a prize with a common value. Prior to exerting effort, each player chooses between an old technology, in which return on effort is certain, and a new technology, in which return on effort is uncertain but on average is equal to the return on effort in the old technology. We characterize symmetric and asymmetric equilibria and show that in equilibrium the new technology is adopted by a proper subset of the players. The results offer an explanation for endogenous emergence of asymmetric technologies in contests.
{"title":"Endogenous technology choice in contests","authors":"Doron Klunover","doi":"10.1016/j.mathsocsci.2025.102491","DOIUrl":"10.1016/j.mathsocsci.2025.102491","url":null,"abstract":"<div><div>We consider a lottery contest between <em>n</em> risk-neutral symmetric players, who compete for a prize with a common value. Prior to exerting effort, each player chooses between an old technology, in which return on effort is certain, and a new technology, in which return on effort is uncertain but on average is equal to the return on effort in the old technology. We characterize symmetric and asymmetric equilibria and show that in equilibrium the new technology is adopted by a proper subset of the players. The results offer an explanation for endogenous emergence of asymmetric technologies in contests.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102491"},"PeriodicalIF":0.7,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.mathsocsci.2025.102489
Yassine Badra , Bertrand Chopard , Huizhong Liu
This paper examines the strategic implications of research joint ventures (RJVs) in an oligopolistic setting with R&D spillovers, focusing on their impact on social welfare. Using the well-known R&D model of d’Aspremont–Jacquemin (AJ), we analyze different R&D cooperation structures: the non-cooperative regime, the R&D cartel regime, the cartelized RJV, and the non-cooperative RJV. Our findings challenge conventional views on the efficiency of RJVs. While the model of Kamien–Muller–Zang (KMZ) consistently predicts that RJVs lead to lower social welfare, we show that in the AJ framework, an RJV can outperform both the standard non-cooperative and cartel regimes when spillovers remain below a certain threshold. This result underscores the importance of model-specific assumptions in assessing R&D cooperation policies and offers valuable insights for industrial policy and antitrust regulation in innovation-driven markets.
{"title":"R&D cooperation and spillovers: When do research joint ventures improve welfare?","authors":"Yassine Badra , Bertrand Chopard , Huizhong Liu","doi":"10.1016/j.mathsocsci.2025.102489","DOIUrl":"10.1016/j.mathsocsci.2025.102489","url":null,"abstract":"<div><div>This paper examines the strategic implications of research joint ventures (RJVs) in an oligopolistic setting with R&D spillovers, focusing on their impact on social welfare. Using the well-known R&D model of d’Aspremont–Jacquemin (AJ), we analyze different R&D cooperation structures: the non-cooperative regime, the R&D cartel regime, the cartelized RJV, and the non-cooperative RJV. Our findings challenge conventional views on the efficiency of RJVs. While the model of Kamien–Muller–Zang (KMZ) consistently predicts that RJVs lead to lower social welfare, we show that in the AJ framework, an RJV can outperform both the standard non-cooperative and cartel regimes when spillovers remain below a certain threshold. This result underscores the importance of model-specific assumptions in assessing R&D cooperation policies and offers valuable insights for industrial policy and antitrust regulation in innovation-driven markets.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102489"},"PeriodicalIF":0.7,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.mathsocsci.2025.102488
Frederik Van De Putte, Stefan Wintein
Claim-strength problems are a distinctive class of allocation problems in which the currency of claims is different from that of the estate that is to be divided. We study mixtures (i.e. convex combinations) of three basic allocation rules for claim-strength problems: the proportional rule, the uniform allocation rule, and the plurality allocation rule. We observe that any such mixture satisfies a generalized transfer axiom in addition to a number of invariance properties. We establish a fundamental representation theorem: taken jointly, these axioms fully characterize the class of all mixtures of the three base rules. This result is tight. From it, we derive characterizations of more specific classes and the three basic rules themselves. We moreover show that within the class of mixtures, the only three rules that satisfy a familiar consistency axiom are the base rules.
{"title":"Claim-strength problems and mixtures: An axiomatic study","authors":"Frederik Van De Putte, Stefan Wintein","doi":"10.1016/j.mathsocsci.2025.102488","DOIUrl":"10.1016/j.mathsocsci.2025.102488","url":null,"abstract":"<div><div>Claim-strength problems are a distinctive class of allocation problems in which the currency of claims is different from that of the estate that is to be divided. We study mixtures (i.e. convex combinations) of three basic allocation rules for claim-strength problems: the proportional rule, the uniform allocation rule, and the plurality allocation rule. We observe that any such mixture satisfies a generalized <em>transfer</em> axiom in addition to a number of <em>invariance</em> properties. We establish a fundamental representation theorem: taken jointly, these axioms fully characterize the class of all mixtures of the three base rules. This result is tight. From it, we derive characterizations of more specific classes and the three basic rules themselves. We moreover show that within the class of mixtures, the only three rules that satisfy a familiar <em>consistency</em> axiom are the base rules.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102488"},"PeriodicalIF":0.7,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.mathsocsci.2025.102490
Pascal Toquebeuf
This paper analyzes a dynamic adverse selection market where buyers hold ambiguous beliefs about seller quality, modeled using neo-additive Choquet capacities and updated via optimistic, pessimistic, and Generalized Bayesian rules. First, we show that the choice of updating heuristic has a direct and systematic effect on the severity of adverse selection. While the optimistic and pessimistic rules invariably mitigate or amplify the problem, respectively, the Generalized Bayesian rule’s impact is conditional, its trajectory toward collapse, efficiency, or a stable partial market depending on a persistent ‘tug-of-war’ between the buyer’s static ambiguity attitude and the evolving probabilistic evidence. Our second main finding is that these immediate effects compound over time, leading to fundamentally different market trajectories. The pessimistic rule can drive the market to complete collapse, the optimistic rule can foster full participation, and the Generalized Bayesian path depends on the interplay between the buyer’s attitude and the evolving evidence. We further analyze how baseline ambiguity and ambiguity aversion modulate these dynamics, uncovering a complex role for ambiguity in shaping the rate of market evolution.
{"title":"Dynamic adverse selection with the best and the worst in mind","authors":"Pascal Toquebeuf","doi":"10.1016/j.mathsocsci.2025.102490","DOIUrl":"10.1016/j.mathsocsci.2025.102490","url":null,"abstract":"<div><div>This paper analyzes a dynamic adverse selection market where buyers hold ambiguous beliefs about seller quality, modeled using neo-additive Choquet capacities and updated via optimistic, pessimistic, and Generalized Bayesian rules. First, we show that the choice of updating heuristic has a direct and systematic effect on the severity of adverse selection. While the optimistic and pessimistic rules invariably mitigate or amplify the problem, respectively, the Generalized Bayesian rule’s impact is conditional, its trajectory toward collapse, efficiency, or a stable partial market depending on a persistent ‘tug-of-war’ between the buyer’s static ambiguity attitude and the evolving probabilistic evidence. Our second main finding is that these immediate effects compound over time, leading to fundamentally different market trajectories. The pessimistic rule can drive the market to complete collapse, the optimistic rule can foster full participation, and the Generalized Bayesian path depends on the interplay between the buyer’s attitude and the evolving evidence. We further analyze how baseline ambiguity and ambiguity aversion modulate these dynamics, uncovering a complex role for ambiguity in shaping the rate of market evolution.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102490"},"PeriodicalIF":0.7,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-21DOI: 10.1016/j.mathsocsci.2025.102477
Noëmi Jacober, Luís Santos-Pinto
In many competitive settings, players must decide not only how hard to work but also how much risk to take. This paper shows that overconfidence—the tendency to overestimate one’s own ability—can lead to surprising strategic behavior in tournaments in which players make both risk and effort choices. We find two key results. First, overconfident players may adopt less risky strategies than rational ones, defying the common belief that overconfidence necessarily drives risk-taking. Second, when overconfident players adopt less risky strategies, they may exert greater effort, revealing a new mechanism by which overconfidence can enhance effort provision.
{"title":"Less risk, more effort: How overconfidence reshapes tournament strategies","authors":"Noëmi Jacober, Luís Santos-Pinto","doi":"10.1016/j.mathsocsci.2025.102477","DOIUrl":"10.1016/j.mathsocsci.2025.102477","url":null,"abstract":"<div><div>In many competitive settings, players must decide not only how hard to work but also how much risk to take. This paper shows that overconfidence—the tendency to overestimate one’s own ability—can lead to surprising strategic behavior in tournaments in which players make both risk and effort choices. We find two key results. First, overconfident players may adopt less risky strategies than rational ones, defying the common belief that overconfidence necessarily drives risk-taking. Second, when overconfident players adopt less risky strategies, they may exert greater effort, revealing a new mechanism by which overconfidence can enhance effort provision.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102477"},"PeriodicalIF":0.7,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145580298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-21DOI: 10.1016/j.mathsocsci.2025.102478
Yuta Saito , Yeming Zhang
This paper investigates the effects of taxation on two-sided platforms, where some agents participate in a single platform (single-homing) and others engage with multiple platforms simultaneously (multi-homing) on both sides of the market (sellers and buyers). Agents’ homing choices are determined endogenously by platform pricing, while platforms set prices in response to ad valorem and unit taxes. We show that raising taxes on one side increases equilibrium prices on both the taxed and untaxed sides. Moreover, the unit tax burden is shared between platforms and users, making taxation more effective at reducing platform profits under multi-homing. This occurs because taxation lowers the number of multi-homers on the taxed side while raising their number on the untaxed side, which in turn prompts platforms to increase prices on the untaxed side. Finally, our welfare analysis identifies the optimal share of multi-homers that maximizes total surplus and clarifies when taxation improves overall welfare.
{"title":"Taxing platforms with multi-homing","authors":"Yuta Saito , Yeming Zhang","doi":"10.1016/j.mathsocsci.2025.102478","DOIUrl":"10.1016/j.mathsocsci.2025.102478","url":null,"abstract":"<div><div>This paper investigates the effects of taxation on two-sided platforms, where some agents participate in a single platform (single-homing) and others engage with multiple platforms simultaneously (multi-homing) on both sides of the market (sellers and buyers). Agents’ homing choices are determined endogenously by platform pricing, while platforms set prices in response to ad valorem and unit taxes. We show that raising taxes on one side increases equilibrium prices on both the taxed and untaxed sides. Moreover, the unit tax burden is shared between platforms and users, making taxation more effective at reducing platform profits under multi-homing. This occurs because taxation lowers the number of multi-homers on the taxed side while raising their number on the untaxed side, which in turn prompts platforms to increase prices on the untaxed side. Finally, our welfare analysis identifies the optimal share of multi-homers that maximizes total surplus and clarifies when taxation improves overall welfare.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"139 ","pages":"Article 102478"},"PeriodicalIF":0.7,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.mathsocsci.2025.102476
Massimiliano Landi , Domenico Menicucci , Domenico Colucci
This paper considers two competing auctions with objects differentiated according to the random utility framework introduced in Perloff and Salop (1985): bidders privately observe their values for the two objects, and values are ex ante i.i.d. across objects and across bidders. For the case of uniform distribution of values, we show that competition under entry fees is less intense than competition under reserve prices in the sense that sellers are better off, and bidders are worse off when competition takes place with entry fees rather than under reserve prices. The key difference between the two settings is that undercutting under entry fees is less effective as a business stealing tool than under reserve prices. This reduces each seller’s incentive to undercut, and in turn increases sellers’ equilibrium revenues. This result contrasts with the equivalence between reserve prices and entry fees in a standard one-object monopoly auction.
{"title":"Competition through entry fees between auctions for differentiated objects","authors":"Massimiliano Landi , Domenico Menicucci , Domenico Colucci","doi":"10.1016/j.mathsocsci.2025.102476","DOIUrl":"10.1016/j.mathsocsci.2025.102476","url":null,"abstract":"<div><div>This paper considers two competing auctions with objects differentiated according to the random utility framework introduced in Perloff and Salop (1985): bidders privately observe their values for the two objects, and values are ex ante i.i.d. across objects and across bidders. For the case of uniform distribution of values, we show that competition under entry fees is less intense than competition under reserve prices in the sense that sellers are better off, and bidders are worse off when competition takes place with entry fees rather than under reserve prices. The key difference between the two settings is that undercutting under entry fees is less effective as a business stealing tool than under reserve prices. This reduces each seller’s incentive to undercut, and in turn increases sellers’ equilibrium revenues. This result contrasts with the equivalence between reserve prices and entry fees in a standard one-object monopoly auction.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"138 ","pages":"Article 102476"},"PeriodicalIF":0.7,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145578708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.mathsocsci.2025.102474
Juan Carlos Gonçalves-Dosantos, Joaquín Sánchez-Soriano
The apportionment problem involves determining how to distribute a given (non-negative) integer number among a group of individuals based on their respective sizes. In electoral systems with proportional representation, this problem arises in two situations: assigning seats to constituencies, if applicable, and distributing seats to political parties within each constituency. This paper addresses the scenario where seats are grouped into lots, extending the standard apportionment problem. We propose and analyze various apportionment methods based on the D’Hondt method for this new problem. Additionally, we examine the political implications of allocating seats not individually but in groups of varying sizes.
{"title":"Apportionment when seats are allocated in lots. The D’Hondt method case and political implications","authors":"Juan Carlos Gonçalves-Dosantos, Joaquín Sánchez-Soriano","doi":"10.1016/j.mathsocsci.2025.102474","DOIUrl":"10.1016/j.mathsocsci.2025.102474","url":null,"abstract":"<div><div>The apportionment problem involves determining how to distribute a given (non-negative) integer number among a group of individuals based on their respective sizes. In electoral systems with proportional representation, this problem arises in two situations: assigning seats to constituencies, if applicable, and distributing seats to political parties within each constituency. This paper addresses the scenario where seats are grouped into lots, extending the standard apportionment problem. We propose and analyze various apportionment methods based on the D’Hondt method for this new problem. Additionally, we examine the political implications of allocating seats not individually but in groups of varying sizes.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"138 ","pages":"Article 102474"},"PeriodicalIF":0.7,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-06DOI: 10.1016/j.mathsocsci.2025.102475
Salvador Candelas
This paper presents a framework for multi-agent settings where each agent must select an action compatible with the choices of others. Agents face a technological constraint that dictates which alternative profiles are feasible, and each agent chooses her preferred option from those available, given the others’ choices. I distinguish between two cases: rival and non-rival alternatives. For a generic problem, I introduce a key axiom, Acyclicity, that characterizes the decision-making process. In the non-rivalrous case, Acyclicity can be further decomposed into two properties: WARP-CC and Joint Acyclicity. Additionally, I propose revealed preference relations to conservatively identify players’ preferences and assess compatibility based on observable, potentially limited choice data. Importantly, the construction and the results presented in this paper do not rely on access to the complete choice observations.
{"title":"Revealing compatible choices","authors":"Salvador Candelas","doi":"10.1016/j.mathsocsci.2025.102475","DOIUrl":"10.1016/j.mathsocsci.2025.102475","url":null,"abstract":"<div><div>This paper presents a framework for multi-agent settings where each agent must select an action <em>compatible</em> with the choices of others. Agents face a technological constraint that dictates which alternative profiles are feasible, and each agent chooses her preferred option from those available, given the others’ choices. I distinguish between two cases: rival and non-rival alternatives. For a generic problem, I introduce a key axiom, Acyclicity, that characterizes the decision-making process. In the non-rivalrous case, Acyclicity can be further decomposed into two properties: WARP-CC and Joint Acyclicity. Additionally, I propose revealed preference relations to conservatively identify players’ preferences and assess compatibility based on observable, potentially limited choice data. Importantly, the construction and the results presented in this paper do not rely on access to the complete choice observations.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"138 ","pages":"Article 102475"},"PeriodicalIF":0.7,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.mathsocsci.2025.102473
Dohui Woo
In the context of dynamic reputational cheap talk, experts are concerned not only with their current signal but also with how their past and future messages shape their perceived ability. This paper studies a two-stage environment in which an expert repeatedly receives private signals and sends unverifiable messages before the true state is revealed. A truth-telling equilibrium arises under a moderate prior on the state and a high prior on ability. Further analysis reveals that equilibria involving early silence are non-generic when messages from the early speaker are taken at face value.
{"title":"Truth-telling in dynamic reputational cheap talk","authors":"Dohui Woo","doi":"10.1016/j.mathsocsci.2025.102473","DOIUrl":"10.1016/j.mathsocsci.2025.102473","url":null,"abstract":"<div><div>In the context of dynamic reputational cheap talk, experts are concerned not only with their current signal but also with how their past and future messages shape their perceived ability. This paper studies a two-stage environment in which an expert repeatedly receives private signals and sends unverifiable messages before the true state is revealed. A truth-telling equilibrium arises under a moderate prior on the state and a high prior on ability. Further analysis reveals that equilibria involving early silence are non-generic when messages from the early speaker are taken at face value.</div></div>","PeriodicalId":51118,"journal":{"name":"Mathematical Social Sciences","volume":"138 ","pages":"Article 102473"},"PeriodicalIF":0.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145473982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"经济学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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