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Madjid Eshaghi Gordji

Publications and source records attributed to Madjid Eshaghi Gordji.

16 recordsLinked to original sources
arXiv2026

Changing the Game: Status-Quo Inertia, Institutional Design, and Equilibrium Transition

Many economic interventions are designed as marginal changes in incentives. Yet in environments shaped by coordination, institutional persistence, and path dependence, such reforms often leave behavior largely unchanged. This paper studies interventions in games when equilibrium selection displays status-quo inertia: if the pre-intervention equilibrium remains a Nash equilibrium after policy, it continues to be selected. In that environment, price-based interventions and simple option expansion may fail even when they improve welfare in a partial-equilibrium sense. By contrast, interventions that modify the feasible action space, especially deletion and replacement interventions, can be substantially more effective because they remove the strategic basis for persistence. We develop a simple framework, derive general results, provide complete proofs, and illustrate the economics with examples from climate transition, platform regulation, financial reform, and industrial modernization. The analysis highlights a basic policy lesson: when inefficient equilibria are institutionally entrenched, the central problem is often not how to price the existing game more finely, but how to change the game itself.

econ.TH↗
arXiv2026

Strategic Inertia and Institutional Change:A Behavioral Model of Price Reforms versus Action Deletion

Why do inefficient practices, technologies, or institutions persist even when su perior alternatives are available? This paper introduces a quantal response equilib rium with status-quo bias (QRE-SB) in which each player incurs a fixed switching cost when deviating from an inherited default action. In a binary coordination game, we compare two policy interventions: a tax on the default action (price-only reform) versus deleting the default action entirely (ban). We prove that there exists a threshold tax below which the status quo persists and above which a transition occurs; notably, this threshold does not depend on the degree of bounded ratio nality. Deleting the default action always forces play to the superior equilibrium, irrespective of switching costs or rationality. Moreover, when the superior equilib rium is Pareto-dominant, deletion yields strictly higher expected welfare than any finite tax that leaves the old action feasible. Numerical simulations illustrate the theoretical predictions. The framework provides a formal foundation for the policy principle that sometimes you must ban, not just tax, with direct applications to climate policy, social media regulation, and international sanctions.

econ.TH↗
arXiv2026

Why Efficient Reforms Fail: Endogenous Game Transformation under Status Quo Bias and Social Preferences

Why do societies remain stuck in inferior institutions even when superior al ternatives are widely recognized? This paper develops a model in which agents choose not only actions within a game but also transformations of the game it self. Transformations may be soft, changing payoffs through taxes or subsidies, or hard, changing feasibility through deletion or replacement of actions. Within a coordination model with status-quo bias (switching cost) and boundedly rational play (logit quantal response), we show that these interventions are qualitatively different: finite taxes shift behavior continuously but cannot eliminate residual use of the inherited action, whereas deletion bypasses inertia by removing the action from the feasible set. We further characterize how antagonistic social preferences at the meta level can block reforms that are individually beneficial for every player. The framework provides a formal rationale for why hard feasibility restrictions of ten dominate soft price incentives under inertia, with direct applications to climate transition (carbon tax vs. fossil-fuel phase-out) and platform regulation (fines vs. deletion of addictive features).

econ.TH↗
arXiv2026

Breaking Status-Quo Inertia in Living Temporal Games: Dynamic Intervention, Implementation, and Structural Design

Westudy how a planner can design dynamic interventions to overcome status-quo inertia in living temporal games, where strategic agents control their state (active, sleep, partially dead) on a temporal network. Building on the continuous-time stochastic game framework of our companion paper, we introduce three intervention classes: bounded transfers (price based), structural modifications (edge deletion, addition, or replacement), and information signals. We formalize the notion of inertia depth and prove a threshold theorem: the status quo equilibrium survives all transfer perturbations whose magnitude is below a critical bound that depends on the remaining horizon. A central structural dominance result shows that for any finite transfer budget there exists a family of games where no bounded price intervention can eliminate the inefficient equilibrium, yet a single edge replacement (continuous-flow to discrete-transport) succeeds. We then study private-information subclasses with static types. Using a uniformization reduction, we prove an impossibility result: no direct mechanism can simultaneously satisfy ex post incentive compatibility, ex post budget balance, and history privacy while always implementing an efficient equilibrium. In the same subclass we construct a dynamic pivot mechanism that achieves second-best efficiency with bounded deficit. Finally, we show that replacing continuous-flow edges by discrete-transport edges weakly expands the set of implementable outcomes, highlighting the importance of temporal semantics for mechanism design. Our results extend the static analysis of [5] to continuous time strategic networks and provide a rigorous foundation for subsequent papers on learning and mean-field design.

econ.TH↗
arXiv2026

Meta-Bayesian Nash Equilibrium: Existence via Kakutani's Fixed Point Theorem

We extend the concept of meta-Nash equilibrium, introduced by Eshaghi Gordji and Bagha [2026] for complete-information games, to environments with incomplete information. We define a meta-Bayesian Nash equilibrium as a profile of type-dependent mixed meta-strategies together with an environmental move such that no player type can profitably deviate and the environment cannot improve its expected payoff. For each transformed game, meta-payoffs are determined by the unique Bayesian Nash equilibrium of that game. Using Kakutani's fixed point theorem, we establish existence under finiteness assumptions on type spaces, meta-actions, and transformations, together with the assumption that each transformed game admits a unique Bayesian Nash equilibrium. Several illustrative examples, including adaptive subsidy competition, cybersecurity protocol selection, and platform rule formation, demonstrate that private information at the meta-level plays an essential role in endogenous game transformation. The framework contains both classical Bayesian games and complete-information meta-games as special cases.

econ.TH↗
arXiv2026

Compound Attrition Games: A Unified Model for Inter- and Intra-Coalition Rivalry

Strategic competitions in the real world, from wars to geopolitical rivalries, often involve coalitions competing against rival groups. These contests are not simple interactions between unified entities, but multilayered processes in which coalitions face external competition while dealing with internal conflicts over resources and strategy. Existing game-theoretic models typically treat inter-coalition rivalry and intra-coalition competition separately. This paper introduces the Compound Coalition-Attrition Game (CCAG), a unified framework that integrates a war of attrition between coalitions with a simultaneous war of attrition within each coalition. In this model, the endurance of a coalition in external competition is determined by the strategic choices of its members, who compete internally for shares of the outcome. We prove the nonexistence of pure-strategy equilibria and characterize the unique mixed-strategy Nash equilibrium. The analysis reveals feedback effects: external competition intensifies internal conflict, while internal discord weakens external performance. A case study compares traditional commodity markets, including gold, copper, and silver, with cryptocurrency markets, including Bitcoin, Ethereum, and Solana, using data from 2018 to 2023 in a simulation framework. The results demonstrate applicability in industrial strategy, corporate decision-making, and geopolitical competition. The CCAG framework provides a tool for analysing complex strategic environments.

econ.GN↗
arXiv2025

The Dynamics of Trust: A Stochastic Levy Model Capturing Sudden Behavioral Jumps

Trust is the invisible glue that holds together the fabric of societies, economic systems, and political institutions. Yet, its dynamics-especially in real-world settings remain unpredictable and difficult to control. While classical trust game models largely rely on discrete frameworks with limited noise, they fall short in capturing sudden behavioral shifts, extreme volatility, or abrupt breakdowns in cooperation.Here, we propose-for the first time a comprehensive stochastic model of trust based on Lévy processes that integrates three fundamental components: Brownian motion (representing everyday fluctuations), Poissonian jump intensity (capturing the frequency of shocks), and random distributions for jump magnitudes. This framework surpasses conventional models by enabling simulations of phenomena such as "sudden trust collapse," "chaotic volatility," and "nonlinear recoveries" dynamics often neglected in both theoretical and empirical studies.By implementing four key simulation scenarios and conducting a detailed parameter sensitivity analysis via 3D and contour plots, we demonstrate that the proposed model is not only mathematically more advanced, but also offers a more realistic representation of human dynamics compared to previous approaches. Beyond its technical contributions, this study outlines a conceptual framework for understanding fragile, jump-driven behaviors in social, economic, and geopolitical systems-where trust is not merely a psychological construct, but an inherently unstable and stochastic variable best captured through Lévy based modeling.

stat.AP↗
arXiv2025

The Trust-Building Game: A Model for Sustainable Cooperation

Trust serves as a fundamental pillar of human interactions, playing a crucial role in economic, social, and political relationships. While traditional models of trust primarily focus on the decision making of the first player, this paper introduces an innovative approach that shifts the emphasis to the decision making processes of the second player. The proposed model employs a repetitive structure through which the first player effectively cultivates the second player's trust through consistent and strategic actions. This framework is applicable across various fields, including public policy, marketing, and international relations. It significantly deepens our understanding of the trust-building process and aids in fostering sustainable cooperation in real world scenarios.

econ.GN↗
arXiv2020

A Weak Form of Amenability of Topological Semigroups and its Applications in Ergodic and Fixed Point Theories

In this paper, we introduce a weak form of amenability on topological semigroups that we call $φ$-amenability, where $φ$ is a character on a topological semigroup. Some basic properties of this new notion are obtained and by giving some examples, we show that this definition is weaker than the amenability of semigroups. As a noticeable result, for a topological semigroup $S$, it is shown that if $S$ is $φ$-amenable, then $S$ is amenable. Moreover, $φ$-ergodicity for a topological semigroup $S$ is introduced and it is proved that under some conditions on $S$ and a Banach space $X$, $φ$-amenability and $φ$-ergodicity of any antirepresntation defined by a right action $S$ on $X$, are equivalent. A relation between $φ$-amenability of topological semigroups and existance of a common fixed point is investigated and by this relation, Hahn-Banach property of topological semigroups in the sense of $φ$-amenability defined and studied.

math.FA↗
arXiv2019

An Analysis of a Fishing Model with Nonlinear Harvesting Function

In this study, considering the importance of how to exploit renewable natural resources, we analyze a fishing model with nonlinear harvesting function in which the players at the equilibrium point do a static game with complete information that, according to the calculations, will cause a waste of energy for both players and so the selection of cooperative strategies along with the agreement between the players is the result of this research.

math.DS↗
arXiv2018

Hyper-rational choice theory

The rational choice theory is based on this idea that people rationally pursue goals for increasing their personal interests. In most conditions, the behavior of an actor is not independent of the person and others' behavior. Here, we present a new concept of rational choice as a hyper-rational choice which in this concept, the actor thinks about profit or loss of other actors in addition to his personal profit or loss and then will choose an action which is desirable to him. We implement the hyper-rational choice to generalize and expand the game theory. Results of this study will help to model the behavior of people considering environmental conditions, the kind of behavior interactive, valuation system of itself and others and system of beliefs and internal values of societies. Hyper-rationality helps us understand how human decision makers behave in interactive decisions.

econ.EM↗
arXiv2018

The logic of behavior of atoms

Understanding of the atomic structures and ways in which the atoms interacting is critical to the understanding of chemistry. In this paper applied the concepts of game theory in explaining reactions between elements of the periodic table. The findings in this study suggest that the coordination and anti coordination, also cooperation and non-cooperation between atoms and molecules lead to bonding formation according to the game theory. Therefore, the chemical behavior and physical treats of any chemical reaction can be predicted. Multiple examples of each batch of the chemical reactions is expressed to support the useability of our claims.

physics.atm-clus↗
arXiv2018

The dynamic framework of decision-making

This work explores dynamics existing in interactions between players. The dynamic system of games is a new attitude to modeling in which an event is modeled using several games. The model allows us to analyze the interplay capabilities and the feasibility objectives of each player after a conflict with other players objectives and capabilities. As an application, we model relations between the Soviet Union and America after World War II to October 1962, by using the dynamic system of games. The dynamic system of games as an important insight clearly has significant implications for modeling strategic interactions in which player pursue goals for increasing their personal interests. In addition, we introduce a new game in which there is a dilemma which this dilemma occurs in most societies. We investigate depends on the claim that each player in this dilemma is hyper-rational. In the concept of hyper-rational, the player thinks about profit or loss of other actors in addition to his personal profit or loss and then will choose an action which is desirable to him. In this dilemma, a weak trust has been created between players, but it is fragile.

physics.soc-ph↗
arXiv2018

Dynamic system of strategic games

Maybe an event can't be modeled completely through on game but there is more chance with several games. With emphasis on players' rationality, we present new properties of strategic games, which result in production of other games. Here, a new attitude to modeling will be presented in game theory as dynamic system of strategic games and its some applications such as analysis of the clash between the United States and Iran in Iraq will be provided. In this system with emphasis on players' rationality, the relationship between strategic games and explicitly the dynamics present in interactions among players will be examined. In addition, we introduce a new game called trickery game. This game shows a good reason for the cunning of some people in everyday life. Cooperation is a hallmark of human society. In many cases, our study provides a mechanism to move towards cooperation between players.

physics.soc-ph↗