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41
Temporal Reasoning in the Situation Calculus
, 1994
"... A fundamental problem in Knowledge Representation is the design of a logical language to express theories about actions and change. One of the most prominent proposals for such a language is John McCarthy's situation calculus, a formalism which views situations as branching towards the future. ..."
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Cited by 139 (11 self)
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A fundamental problem in Knowledge Representation is the design of a logical language to express theories about actions and change. One of the most prominent proposals for such a language is John McCarthy's situation calculus, a formalism which views situations as branching towards the future. The situation calculus has been criticized for imposing severe representational limitations. For example, actions cannot be concurrent, properties change discretely, etc. In this thesis we show that many of these limitations can be overcome. Our work builds upon the discrete situation calculus and on Reiter's monotonic solution to the frame problem. A limitation of Reiter's approach is that it does not allow for state constraints. However, Lin and Reiter have made progress by providing a correctness criterion by which one can determine if an axiomatization can be said to solve the frame problem for theories that include state constraints.
Nonmonotonic Reasoning in the Framework of Situation Calculus
 Artificial Intelligence
, 1991
"... Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that si ..."
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Cited by 138 (0 self)
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Most of the solutions proposed to the Yale shooting problem have either introduced new nonmonotonic reasoning methods (generally involving temporal priorities) or completely reformulated the domain axioms to represent causality explicitly. This paper presents a new solution based on the idea that since the abnormality predicate takes a situational argument, it is important for the meanings of the situations to be held constant across the various models being compared. This is accomplished by a simple change in circumscription policy: when Ab is circumscribed, Result (rather than Holds) is allowed to vary. In addition, we need an axiom ensuring that every consistent situation is included in the domain of discourse. Ordinary circumscription will then produce the intuitively correct answer. Beyond its conceptual simplicity, the solution proposed here has additional advantages over the previous approaches. Unlike the approach that uses temporal priorities, it can support reasoning backward...
A Circumscriptive Calculus of Events
 Artificial Intelligence
, 1995
"... A calculus of events is presented in which domain constraints, concurrent events, and events with nondeterministic effects can be represented. The paper offers a nonmonotonic solution to the frame problem for this formalism that combines two of the techniques developed for the situation calculus, ..."
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Cited by 77 (11 self)
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A calculus of events is presented in which domain constraints, concurrent events, and events with nondeterministic effects can be represented. The paper offers a nonmonotonic solution to the frame problem for this formalism that combines two of the techniques developed for the situation calculus, namely causal and statebased minimisation. A theorem is presented which guarantees that temporal projection will not interfere with minimisation in this solution, even in domains with ramifications, concurrency, and nondeterminism. Finally, the paper shows how the formalism can be extended to cope with continuous change, whilst preserving the conditions for the theorem to apply. 1 Introduction The frame problem was first described by McCarthy and Hayes in the Sixties [23], and has occupied the thoughts of AI researchers ever since. In a nutshell, the problem is this: if we deploy classical logic in a straightforward way to describe the effects of actions, we have to represent explicitl...
Embracing Occlusion in Specifying the Indirect Effects of Actions
, 1996
"... In this paper, we extend PMON, a logic for reasoning about action and change, with causal rules which are used to specify the indirect effects of actions. The extension, called PMON(RCs), has the advantage of using explicit time, includes actions with durations, nondeterministic actions, allows part ..."
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Cited by 52 (8 self)
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In this paper, we extend PMON, a logic for reasoning about action and change, with causal rules which are used to specify the indirect effects of actions. The extension, called PMON(RCs), has the advantage of using explicit time, includes actions with durations, nondeterministic actions, allows partial specification of the timing and order of actions and has been assessed correct for at least the KIA class of action scenarios within the Features and Fluents framework. Most importantly, the circumscription policy used is easily shown to be reducible to the firstorder case which insures that standard theorem proving techniques and their optimizations may be used to compute entailment. In addition, we show how the occlusion concept previously used to deal with duration and nondeterministic actions proves to be equally versatile in representing causal constraints and delayed effects of actions. We also discuss related work and consider the strong correspondence between our work and recent...
The Event Calculus in Classical Logic  Alternative Axiomatisations
, 1999
"... We present several alternative classical logic axiomatisations of the Event Calculus, a narrative based formalism for reasoning about actions and change. We indicate the range of applicability and key characteristics of each alternative formulation. ..."
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Cited by 49 (1 self)
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We present several alternative classical logic axiomatisations of the Event Calculus, a narrative based formalism for reasoning about actions and change. We indicate the range of applicability and key characteristics of each alternative formulation.
Nested Abnormality Theories
 Artificial Intelligence
, 1995
"... We propose a new approach to the use of circumscription for representing knowledge. Nested abnormality theories are similar to simple abnormality theories introduced by McCarthy, except that their axioms may have a nested structure, with each level corresponding to another application of the circ ..."
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Cited by 48 (5 self)
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We propose a new approach to the use of circumscription for representing knowledge. Nested abnormality theories are similar to simple abnormality theories introduced by McCarthy, except that their axioms may have a nested structure, with each level corresponding to another application of the circumscription operator. The new style of applying circumscription sometimes leads to more economical and elegant formalizations. Mathematical properties of nested abnormality theories may be easier to investigate. These advantages are demonstrated by recasting several familiar applications of circumscription in the new format, including some examples of inheritance hierarchies, the domain closure assumption and causal minimization. Nested abnormality theories provide also a convenient representation for the explanation closure approach to the frame problem developed by Schubert.
Some alternative formulations of the event calculus
 Computer Science; Computational Logic; Logic programming and Beyond
, 2002
"... Abstract. The Event Calculus is a narrative based formalism for reasoning about actions and change originally proposed in logic programming form by Kowalski and Sergot. In this paper we summarise how variants of the Event Calculus may be expressed as classical logic axiomatisations, and how under ce ..."
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Cited by 43 (3 self)
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Abstract. The Event Calculus is a narrative based formalism for reasoning about actions and change originally proposed in logic programming form by Kowalski and Sergot. In this paper we summarise how variants of the Event Calculus may be expressed as classical logic axiomatisations, and how under certain circumstances these theories may be reformulated as “action description language ” domain descriptions using the Language E. This enables the classical logic Event Calculus to inherit various provably correct automated reasoning procedures recently developed for E. 1
Two Counterexamples Related to Baker's Approach to the Frame Problem
 Artificial Intelligence
, 1994
"... Andrew Baker's approach to reasoning about actions is the most robust circumscriptive approach currently known. Investigation of its applicability to nondeterministic actions reveals that this approach does not allow us to draw some intuitively plausible conclusions. Also, it does not always ge ..."
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Cited by 29 (3 self)
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Andrew Baker's approach to reasoning about actions is the most robust circumscriptive approach currently known. Investigation of its applicability to nondeterministic actions reveals that this approach does not allow us to draw some intuitively plausible conclusions. Also, it does not always generate the proper existence of situations axiom. The limitations are traced to an unexpected interference of the axioms encoding observations with the minimization. A modification that avoids the shortcomings is suggested. 1 Introduction It has long been recognized [McCarthy and Hayes, 1969] that the frame problem, viz. the problem of formalizing in a natural and succinct fashion what is unchanged as a result of performing an action, is central to reasoning about change. This problem has been one of the motivating factors behind the emergence of several nonmonotonic formalisms [McCarthy, 1980; Reiter, 1980; McDermott and Doyle, 1980] in the 80's. McCarthy in his 1986 paper ([McCarthy, 1986]) p...
Actions with Indirect Effects
 In KR 94
, 1994
"... We define and study a highlevel language for describing actions that extends the language A introduced by Gelfond and Lifschitz. The new language, AR 0 , allows us to describe actions with indirect effects (ramifications) and simple forms of nondeterminism. A translation from AR 0 into a formalism ..."
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Cited by 23 (4 self)
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We define and study a highlevel language for describing actions that extends the language A introduced by Gelfond and Lifschitz. The new language, AR 0 , allows us to describe actions with indirect effects (ramifications) and simple forms of nondeterminism. A translation from AR 0 into a formalism based on circumscription is proved to be sound and complete. 1 Introduction Describing properties of actions and their effects on the state of the world has long been considered one of the central problems in the theory of knowledge representation. The approaches proposed in the literature differ by the temporal ontologies they use (linear or branching time, time points or intervals, situations, events or histories), by the logic used (classical logic, its nonmonotonic extensions, logic programming), and by other details of the formalization (which objects are reified, which circumscription policy is used, etc.). In this area of research, it turned out to be difficult to discuss the possi...