Forgetting has been addressed in various areas in KR, including classical logic, logicprogramming, modal logic, and description logics. Here, we view forgetting as an abstract operator, independent of the underlying ...
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Forgetting has been addressed in various areas in KR, including classical logic, logicprogramming, modal logic, and description logics. Here, we view forgetting as an abstract operator, independent of the underlying logic. We argue that forgetting amounts to a reduction in the signature of a language of a logic, and that the result of forgetting elements of a signature in a theory is the set of logical consequences over the reduced language. this definition offers several advantages. It provides a uniform approach to forgetting, applicable to any logic with a well-defined consequence relation. Obtained results are thus applicable to all subsumed formal systems, and typically are obtained much more straightforwardly. the approach also leads to insights with respect to specific logics: forgetting in first-order logic is somewhat different from the accepted approach;and the definition applied to logic programs yields a new syntax-independent notion of forgetting.
We consider the problem of representing and reasoning about computer programs, and propose a translator from a core procedural iterative programming language to first-order logic with quantification over the domain of...
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We consider the problem of representing and reasoning about computer programs, and propose a translator from a core procedural iterative programming language to first-order logic with quantification over the domain of natural numbers that includes the usual successor function and the "less than" linear order, essentially a first-order logic with a discrete linear order. Unlike Hoare's logic, our approach does not rely on loop invariants. Unlike typical temporal logic specification of a program, our translation does not require a transition system model of the program, and is compositional on the structures of the program. Some non-trivial examples are given to show the effectiveness of our translation for proving properties of programs.
Aggregative deontic detachment is a new form of deontic detachment that keeps track of previously detached obligations. We argue that it handles iteration of successive detachments in a more principled manner than the...
Aggregative deontic detachment is a new form of deontic detachment that keeps track of previously detached obligations. We argue that it handles iteration of successive detachments in a more principled manner than the traditional systems do. To study this new form of deontic detachment, we introduce a 'minimal' logic for aggregative deontic detachment, and we discuss various properties of the logic.
Our aim is to develop techniques for reasoning about game-like concurrent systems, where the components of the system act rationally and strategically in pursuit of logically-specified goals. We first present a comput...
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Our aim is to develop techniques for reasoning about game-like concurrent systems, where the components of the system act rationally and strategically in pursuit of logically-specified goals. We first present a computational model for such systems, and investigate its properties. We then define and investigate a branching-time logic for reasoning about the equilibrium properties of such systems. the key operator in this logic is a path quantifier [NE](phi), which asserts that y holds on all Nash equilibrium computations of the system.
the paper presents an extension of temporal epistemic logicthat adds "strategic" agents in a way that allows standard epistemic operators to capture what agents could deduce from knowledge of the strategies...
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the paper presents an extension of temporal epistemic logicthat adds "strategic" agents in a way that allows standard epistemic operators to capture what agents could deduce from knowledge of the strategies of some subset of the set of agents. A number of examples are presented to demonstrate the broad applicability of the framework, including reasoning about implementations of knowledge-based programs, game theoretic solution concepts and notions from computer security. It is shown that notions from several variants of alternating temporal epistemic logic can be expressed. the framework is shown to have a decidable model checking problem.
We examine several belief change operations in the light of Dynamic logic of Propositional Assignments DL-PA. We show that we can encode in a systematic way update operations (such as Winslett's 'Possible Mode...
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We examine several belief change operations in the light of Dynamic logic of Propositional Assignments DL-PA. We show that we can encode in a systematic way update operations (such as Winslett's 'Possible Models Approach') and revision operations (such as Dalai's) as particular DL-PA programs. Every DL-PA formula being equivalent to a boolean formula, we obtain syntactical counterparts for all these belief change operations.
the paper develops a branching-time ontology that maintains the classical restriction of forward movement through a temporal tree structure, but permits the representation of paths in which one can perform inferences ...
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the paper develops a branching-time ontology that maintains the classical restriction of forward movement through a temporal tree structure, but permits the representation of paths in which one can perform inferences about time-travel scenarios. Central to the ontology is the notion of an agent embodiment whose beliefs are equivalent to those of an agent who has time-traveled from the future.
In this paper we present a tableau-based method to decide the satisfiability of formulas in ATEL, an extension of the alternating-time temporal logic ATL including epistemic modalities for individual knowledge. Specif...
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In this paper we present a tableau-based method to decide the satisfiability of formulas in ATEL, an extension of the alternating-time temporal logic ATL including epistemic modalities for individual knowledge. Specifically, we analyse satisfiability of ATEL formulas under a number of conditions. We evaluate the assumptions of synchronicity and of a unique initial state, which have been proposed in the context of Interpreted Systems. Also, we consider satisfiability at an initial state as opposed to any state in the system. We introduce a tableau-based decision procedure for each of these combinations. Moreover, we adopt an agent-based approach to satisfiability, namely, the decision procedure returns a set of agents inducing a concurrent game structure that satisfies the relevant specification.
Boolean games are a framework for reasoning about the rational behaviour of agents, whose goals are formalized using propositional formulas. they offer an attractive alternative to normal-form games, because they allo...
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Boolean games are a framework for reasoning about the rational behaviour of agents, whose goals are formalized using propositional formulas. they offer an attractive alternative to normal-form games, because they allow for a more intuitive and more compact encoding. Unfortunately, however, there is currently no general, tailor-made method available to compute the equilibria of Boolean games. In this paper, we introduce a method for finding the pure Nash equilibria based on disjunctive answer set programming Our method is furthermore capable of finding the core elements and the Pareto optimal equilibria, and can easily be modified to support other forms of optimality, thanks to the declarative nature of disjunctive answer set programming Experimental results clearly demonstrate the effectiveness of the proposed method.
Graphical belief models are compact and powerful tools for representing and reasoning under uncertainty. Possibilistic networks are graphical belief models based on possibility theory. In this paper, we address reason...
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Graphical belief models are compact and powerful tools for representing and reasoning under uncertainty. Possibilistic networks are graphical belief models based on possibility theory. In this paper, we address reasoning under uncertain inputs in both quantitative and qualitative possibilistic networks. More precisely, we first provide possibilistic counterparts of Pearl's methods of virtual evidence then compare them withthe possibilistic counterparts of Jeffrey's rule of conditioning. As in the probabilistic setting, the two methods are shown to be equivalent in the quantitative setting regarding the existence and uniqueness of the solution. However in the qualitative setting, Pearl's method of virtual evidence which applies directly on graphical models disagrees with Jeffrey's rule and the virtual evidence method. the paper provides the precise situations where the methods are not equivalent. Finally, the paper addresses related issues like transformations from one method to another and commutativity.
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