Strategic Reasoning in Game Theory

Game theory in AI is a powerful mathematical framework largely applied in the last three decades for the strategic reasoning in multi-agent systems. Seminal works along this line started with turn-based two-player games (under perfect and imperfect information) to check the correctness of a system against an unpredictable environment. Then, large effort has been devoted to extend those works to the multi-agent setting and, specifically, to efficiently reasoning about important solution concepts such as Nash Equilibria and the like. Breakthrough contributions along this direction concern the introduction of logics for the strategic reasoning such as Alternating-time Temporal Logic (ATL), Strategy Logic (SL), and their extensions. Two-player games and logics for the strategic reasoning are nowadays very active areas of research. In this thesis we significantly advance the work along both these two lines of research by providing fresh studies and results of practical application. We start with two-player reachability games and first investigate the problem of checking whether a designed player has more than a winning strategy to reach a target. We investigate this question under both perfect and imperfect information. We provide an automata-based solution that requires linear-time, in the perfect information setting, and exponential-time, in the imperfect one. In both cases, the results are tight. Then, we move to multi-player concurrent games and study the following specific setting: (i) Player_0's objective is to reach a target W, and (ii) the opponents are trying to stop this but have partial observation about Player_0's actions. We study the problem of deciding whether the opponents can prevent Player_0 to reach W. We show, using an automata-theoretic approach that, assuming the opponents have the same partial observation and play under uniformity, the problem is in ExpTime. We recall that, in general, multi-player reachability games with imperfect information are undecidable. Then, we move to the more expressive framework of logics for the strategic reasoning. We first introduce and study two graded extensions of SL, namely GSL and GradedSL. By the former, we define a graded version over single strategy variables, i.e. "there exist at least g different strategies", where the strategies are counted semantically. We study the model checking-problem for GSL and show that for its fragment called vanilla GSL[1G] the problem is PTime-complete. By GradedSL, we consider a graded version over tuple of strategy variables and use a syntactic counting over strategies. By means of GradedSL we show how to count the number of different strategy profiles that are Nash equilibria (NE). By analyzing the structure of the specific formulas involved, we conclude that the important problem of checking for the existence of a unique NE can be solved in 2ExpTime, which is not harder than merely checking for the existence of such an equilibrium. Finally, we adopt the view of bounded rationality, and look only at "simple" strategies in specifications of agents’ abilities. We formally define what "simple" means, and propose a variant of plain ATL, namely NatATL, that takes only such strategies into account. We study the model checking problem for the resulting semantics of ability and obtain tight results. The positive results achieved with NatATL encourage for the investigation of simple strategies over more powerful logics, including SL

Fuzzy Sets in Business Management, Finance, and Economics

This book collects fifteen papers published in s Special Issue of Mathematics titled “Fuzzy Sets in Business Management, Finance, and Economics”, which was published in 2021. These paper cover a wide range of different tools from Fuzzy Set Theory and applications in many areas of Business Management and other connected fields. Specifically, this book contains applications of such instruments as, among others, Fuzzy Set Qualitative Comparative Analysis, Neuro-Fuzzy Methods, the Forgotten Effects Algorithm, Expertons Theory, Fuzzy Markov Chains, Fuzzy Arithmetic, Decision Making with OWA Operators and Pythagorean Aggregation Operators, Fuzzy Pattern Recognition, and Intuitionistic Fuzzy Sets. The papers in this book tackle a wide variety of problems in areas such as strategic management, sustainable decisions by firms and public organisms, tourism management, accounting and auditing, macroeconomic modelling, the evaluation of public organizations and universities, and actuarial modelling. We hope that this book will be useful not only for business managers, public decision-makers, and researchers in the specific fields of business management, finance, and economics but also in the broader areas of soft mathematics in social sciences. Practitioners will find methods and ideas that could be fruitful in current management issues. Scholars will find novel developments that may inspire further applications in the social sciences

Collective agency:From philosophical and logical perspectives

People inhabit a vast and intricate social network nowadays. In addition to our own decisions and actions, we confront those of various groups every day. Collective decisions and actions are more complex and bewildering compared to those made by individuals. As members of a collective, we contribute to its decisions, but our contributions may not always align with the outcome. We may also find ourselves excluded from certain groups and passively subjected to their influences without being aware of the source. We are used to being in overlapping groups and may switch identities, supporting or opposing the claims of particular groups. But rarely do we pause to think: What do we talk about when we talk about groups and their decisions?At the heart of this dissertation is the question of collective agency, i.e., in what sense can we treat a group as a rational agent capable of its action. There are two perspectives we take: a philosophical and logical one. The philosophical perspective mainly discusses the ontological and epistemological issues related to collective agency, sorts out the relevant philosophical history, and argues that the combination of a relational view of collective agency and a dispositional view of collective intentionality provides a rational and realistic account. The logical perspective is associated with formal theories of groups, it disregards the psychological content involved in the philosophical perspective, establishes a logical system that is sufficiently formal and objective, and axiomatizes the nature of a collective

Amazon and Platform Antitrust

With its decision in Ohio v. American Express, the U.S. Supreme Court for the first time embraced the recently developed, yet increasingly prolific, concept of the two-sided platform. Through advances in technology, platforms, which serve as intermediaries allowing two groups to transact, are increasingly ubiquitous, and many of the biggest tech companies operate in this fashion. Amazon Marketplace, for example, provides a platform for third-party vendors to sell directly to consumers through Amazon’s web and mobile interfaces. At the same time that platforms and their scholarship have evolved, a burgeoning antitrust movement has also developed which focuses on the impact of the dominance of these tech companies and the fear that current antitrust laws are ill-equipped to prevent any potential anticompetitive behavior. Many of those who feel this way worried that American Express, which decided whether a plaintiff alleging anticompetitive behavior by a two- sided platform would have to show harm to both sides of the market to make a prima facie case, would give companies like Amazon even more power. This Note argues that while the case could be interpreted in such a way, because Amazon and similarly situated platforms possess a great degree of control over their users—in some cases competing with them directly—it would be unwise to do so

Sustainability of systems interoperability in dynamic business networks

Dissertação para obtenção do Grau de Doutor em Engenharia Electrotécnica e de ComputadoresCollaborative networked environments emerged with the spread of the internet, contributing to overcome past communication barriers, and identifying interoperability as an essential property to support businesses development. When achieved seamlessly, efficiency is increased in the entire product life cycle support. However, due to the different sources of knowledge, models and semantics, enterprise organisations are experiencing difficulties exchanging critical information, even when they operate in the same business environments. To solve this issue, most of them try to attain interoperability by establishing peer-to-peer mappings with different business partners, or use neutral data and product standards as the core for information sharing, in optimized networks. In current industrial practice, the model mappings that regulate enterprise communications are only defined once, and most of them are hardcoded in the information systems. This solution has been effective and sufficient for static environments, where enterprise and product models are valid for decades. However, more and more enterprise systems are becoming dynamic, adapting and looking forward to meet further requirements; a trend that is causing new interoperability disturbances and efficiency reduction on existing partnerships. Enterprise Interoperability (EI) is a well established area of applied research, studying these problems, and proposing novel approaches and solutions. This PhD work contributes to that research considering enterprises as complex and adaptive systems, swayed to factors that are making interoperability difficult to sustain over time. The analysis of complexity as a neighbouring scientific domain, in which features of interoperability can be identified and evaluated as a benchmark for developing a new foundation of EI, is here proposed. This approach envisages at drawing concepts from complexity science to analyse dynamic enterprise networks and proposes a framework for sustaining systems interoperability, enabling different organisations to evolve at their own pace, answering the upcoming requirements but minimizing the negative impact these changes can have on their business environment

Framework for the selection of acquisition targets applied in the commercial aerospace industry

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; in conjunction with the Leaders for Global Operations Program at MIT, 2010.Title-page reads "Master of Science in Management."-- Student received an M.B.A per June 2010 Degree List, Office of the Registrar, MIT. Cataloged from PDF version of thesis.Includes bibliographical references (p. 87-89).Acquisitions are costly, even the ones that never happen. They require a significant commitment of resources involving multi-disciplinary teams examining all aspects of a business. This can come at a significant cost if either the acquisition does not produce the value that was originally expected or if the acquisition process is aborted all together. Clearly, it is critical to be confident in the initial selection, when investing capital and resources to carry out the lengthy investigation process. However, while there is exhaustive research on the detailed evaluation of a target, there is very little published about the preliminary selection process. In this thesis, we demonstrate a methodology for acquisition target selection. We propose a method of metric-based ranking of targets for criteria defined in 3 dimensions. The first is a measure of how a target meets the Strategic Goals of the acquiring company. This is critical not only to measure a target, but to clarify and create alignment among the leadership of the company for the purpose of the acquisition. The second dimension is a measure of Acquisition Fit. This represents a rough measure of likelihood of integration success of a target. The metrics in this dimension are based on research into attributes of acquisition failures. The final dimension is a Financial Impact measure, which represents a rough business case for the acquisition. In the second half of this thesis, we introduce a case study of this methodology being applied in the large commercial aircraft (LCA) industry at Spirit AeroSystems, Inc. This case study demonstrates the application of this methodology with the necessary industry analysis, internal and external technology evaluation and implementation challenges. During this case study, the LCA industry is undergoing a period of technological disruption and re-distribution of engineering responsibilities. These shifts in the industry structure require additional rigor in evaluation of technological and engineering needs and capabilities. Experience is statistically a strong indicator of success in M&A. We hope to lower the learning curve costs and associated risk by capturing research of best practices in a manageable process for M&A target selection.by Michael Tajima.M.B.A.S.M

The Origins of Mutual Forbearance: Learning to Trust to Mutually Forbear

Multi-market contact can either escalate or deescalate rivalry. Recent empirical work has revealed an inverted U-shaped relationship between multi-market contact and rivalry. These findings have lead many to suggest that mutual forbearance (MF), a switch from competition to cooperation across markets, is a natural outcome of increasing multi-market contact between two firms. Despite the relatively widespread acceptance of this suggestion, we do not have a theoretically grounded explanation for how this switch from rivalry to mutual forbearance occurs. This dissertation takes up this task. Theories of learning and trust are used as the grounding for the development of a theoretical model of the process by which multi-market rivals switch from competition to cooperation across markets. The model is tested using data from the U.S. Scheduled Passenger Airline Industry. Results support the general theoretical foundations of the model and provide new insights into the genesis of mutual forbearance

Discourses on social software

Can computer scientists contribute to the solution of societal problems? Can logic help to model social interactions? Are there recipes for making groups with diverging preferences arrive at reasonable decisions? Why is common knowledge important for social interaction? Does the rational pursuit of individual interests put the public interest in danger, and if so, why? Discourses on Social Software sheds light on these and similar questions. This book offers the reader an ideal introduction to the exciting new field of social software. It shows in detail the many ways in which the seemingly abstract sciences of logic and computer science can be put to use to analyse and solve contemporary social problems. The unusual format of a series of discussions among a logician, a computer scientist, a philosopher and some researchers from other disciplines encourages the reader to develop his own point of view. The only requirements for reading this book are a nodding familiarity with logic, a curious mind, and a taste for spicy debate.Kunnen de computerwetenschappers bijdragen aan een oplossing van sociale problemen? Kan logica gebruikt worden om sociale interactie te modelleren? Zijn er regels op te stellen om groepen met afwijkende voorkeuren tot redelijke besluiten te laten komen? Discourses on Social Software biedt de lezer een ideale inleiding op (nog nieuwe) gebied van sociale software. Het toont in detail de vele manieren waarin de schijnbaar abstracte wetenschappen van logica en computerwetenschap aan het werk kunnen worden gezet om eigentijdse sociale problemen te analyseren en op te lossen. Door de ongebruikelijke aanpak in dit boek, namelijk door discussies tussen een logicus, een computerwetenschapper, een filosoof en onderzoekers uit andere disciplines, wordt de lezer aangemoedigd zijn eigen standpunt te ontwikkelen. De enige vereisten om dit boek te lezen zijn enige vertrouwdheid met de logica, een nieuwsgierige geest, en liefde voor een pittig debat