Search

The article proposes a formal semantics of happiness and sadness modalities in the imperfect information setting. It shows that these modalities are not definable through each other and gives a sound and complete axiomatization of their properties. [ABSTRACT FROM AUTHOR]

The article proposes a trimodal logical system that can express the strategic ability of coalitions to learn from their experience. The main technical result is the completeness of the proposed system. [ABSTRACT FROM AUTHOR]

The article studies two forms of responsibility in the setting of strategic games with imperfect information. They are referred to as seeing-to-it responsibility and counterfactual responsibility. It shows that counterfactual responsibility is definable through seeing-to-it, but not the other way around. The article also proposes a sound and complete bimodal logical system that describes the interplay between the seeing-to-it modality and the individual ex ante knowledge modality. [ABSTRACT FROM AUTHOR]

The existence of a coalition strategy to achieve a goal does not necessarily mean that the coalition has enough information to know how to follow the strategy. Neither does it mean that the coalition knows that such a strategy exists. The article studies an interplay between the distributed knowledge, coalition strategies, and coalition “know-how” strategies. The main technical result is a sound and complete trimodal logical system that describes the properties of this interplay. [ABSTRACT FROM AUTHOR]

The article proposes a way to add marketing into the standard threshold model of social networks. Within this framework, the article studies logical properties of the influence relation between sets of agents in social networks. Two different forms of this relation are considered: one for promotional marketing and the other for preventive marketing. In each case a sound and complete logical system describing properties of the influence relation is proposed. Both systems could be viewed as extensions of Armstrong's axioms of functional dependency from the database theory. [ABSTRACT FROM AUTHOR]

The article proposes a logical framework for reasoning about agents' ability to protect their privacy by hiding certain information from a privacy intruder. It is assumed that the knowledge of the intruder is derived from the observation of pieces of evidence and that there is a cost associated with the elimination of the evidence. The logical framework contains a modal operator labeled by a group of agents and a total budget available to this group. The key contribution of this work is the proposed incorporation of the cost factor into privacy protection reasoning within the standard modal logic framework. The main technical result are the soundness and completeness theorems for the introduced logical system with respect to a formally defined semantics. [ABSTRACT FROM AUTHOR]

The article introduces a modal logic for reasoning about combined effect of economic policies imposed on a group of rational agents. Modalities in this language are labelled by policies applied to the players in a strategic game. The resulting logical system allows to reason about properties that are true in all Nash equilibria of the game modified by a specific policy. The main technical result is the completeness theorem for the proposed logical system. [ABSTRACT FROM AUTHOR]

The notion of interchangeability has been introduced by John Nash in one of his original papers on equilibria. This article studies properties of Nash equilibria interchangeability in cellular games that model behaviour of infinite chain of homogeneous economic agents. The article shows that there are games in the which strategy of any given player is interchangeable with strategies of players in an arbitrary large neighbourhood of the given player, but is not interchangeable with the strategy of a remote player outside of the neighbourhood. The main technical result is a sound and complete logical system describing universal properties of interchangeability common to all cellular games. [ABSTRACT FROM AUTHOR]

The notion of interchangeability was introduced by Nash in one of his original papers on equilibria in strategic games. It has been recently shown that propositional theory of this relation is the same as propositional theories of the non-deducibility relation in the information flow theory, the independence relation in probability theory, and the non-interference relation in concurrency theory. Propositional theories of conditional non-deducibility and conditional independence have been studied before. This article introduces a notion of conditional interchangeability and gives complete axiomatization of this relation with conditioning by a single player. [ABSTRACT FROM AUTHOR]

The interchangeability property of Nash equilibria in two-player zero-sum games is well known. This article studies possible generalizations of this property to multi-player zero-sum games.Aform of interchangeability property for strict Nash equilibria in such games is established. It is also shown, by proving a completeness theorem, that strict Nash equilibria do not satisfy any other non-trivial properties. [ABSTRACT FROM PUBLISHER]

The article proposes a new approach to reasoning about knowledge and strategies in multiagent systems. It emphasizes data, not agents, as the source of strategic knowledge. The approach brings together Armstrong's functional dependency from database theory, a data-informed knowledge modality based on a recent work by Baltag and van Benthem, and a newly proposed data-informed strategy modality. The main technical result is a sound and complete logical system that describes the interplay between these three logical operators. [ABSTRACT FROM AUTHOR]

Abstract: The article investigates information flow properties of symmetric multi-party protocols. It gives a sound and complete axiomatic system for properties of the functional dependence predicate that are common to all protocols with the same group of symmetries. [Copyright &y& Elsevier]

If an agent, or a coalition of agents, knows that it has a strategy to achieve a certain outcome, it does not mean that the agent knows what the strategy is. Even if the agent knows what the strategy is, she might not know the price of executing this strategy. The article considers modality "the coalition not only knows the strategy, but also knows an upper bound on the price of executing the strategy". The main technical result is a sound and complete bimodal logical system that describes the interplay between this modality and the distributed knowledge modality. [ABSTRACT FROM AUTHOR]

Blameworthiness of an agent or a coalition of agents can be defined in terms of the principle of alternative possibilities: for the coalition to be responsible for an outcome, the outcome must take place and the coalition should be a minimal one that had a strategy to prevent the outcome. In this article we argue that in the settings with imperfect information, not only should the coalition have had a strategy, but it also should be the minimal one that knew that it had a strategy and what the strategy was. The main technical result of the article is a sound and complete bimodal logic that describes the interplay between knowledge and blameworthiness in strategic games with imperfect information. [ABSTRACT FROM AUTHOR]