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Michael Thielscher - One of the best experts on this subject based on the ideXlab platform.
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Artificial Intelligence 111(1–2): 277–299 (1999). From Situation Calculus to Fluent Calculus: State Update Axioms as a Solution to the Inferential Frame Problem
2008Co-Authors: Michael ThielscherAbstract:Abstract. Successor State axioms provide a solution to the famous Frame Problem as far as the representational aspect is concerned. Solving in classical, monotonic logic the additional inferential Frame Problem, on the other hand, was the major motivation for the development of the Fluent Calculus a decade or so ago. Yet the expressiveness of the latter in comparison to the Situation Calculus remained a largely open question until today. In this note, we derive a novel version of the Fluent Calculus by gradually applying the principle of reification to Successor State axioms in order to address the inferential Frame Problem without losing the representational merits. Our approach results in a fully mechanic method for the generation of State update axioms from any collection of Situation Calculus-style effect axioms for deterministic actions, provided the actions do not have potentially infinitely many effects. The axiomatization thus obtained is proved essentially equivalent to the corresponding axiomatization which uses Successor State axioms. Keywords. Cognitive Robotics, Frame Problem.
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from situation calculus to fluent calculus State update axioms as a solution to the inferential frame problem
1999Co-Authors: Michael ThielscherAbstract:Successor State axioms provide a solution to the famous Frame Problem as far as the representational aspect is concerned. Solving in classical, monotonic logic the additional inferential Frame Problem, on the other hand, was the major motivation for the development of the Fluent Calculus a decade or so ago. Yet the expressiveness of the latter in comparison to the Situation Calculus remained a largely open question until today. In this note, we derive a novel version of the Fluent Calculus by gradually applying the principle of reification to Successor State axioms in order to address the inferential Frame Problem without losing the representational merits. Our approach results in a fully mechanic method for the generation of State update axioms from any collection of Situation Calculus-style effect axioms for deterministic actions, provided the actions do not have potentially infinitely many effects. The axiomatization thus obtained is proved essentially equivalent to the corresponding axiomatization which uses Successor State axioms.
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towards State update axioms reifying Successor State axioms
1998Co-Authors: Michael ThielscherAbstract:Successor State axioms are an optimal solution to the famous Frame Problem in reasoning about actions|but only as far as its representational aspect is concerned. We show how by gradually applying the principle of reification to these axioms, one can achieve gradual improvement regarding the inferential aspect without losing the representational merits. The resulting concept of State update axioms constitutes a novel version of what is known as the Fluent Calculus. We illustrate that under the provision that actions have no so-called open effects, any Situation Calculus specification can be transformed into an essentially equivalent Fluent Calculus specification, in which at the same time the representational and the inferential aspect of the Frame Problem are addressed. This alternative access to the Fluent Calculus both clarifies its role in relation to the most popular axiomatization paradigm and should help to enhance its acceptance.
Robert Demolombe - One of the best experts on this subject based on the ideXlab platform.
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belief revision in the situation calculus without plausibility levels
2006Co-Authors: Robert Demolombe, Pilar Pozos ParraAbstract:The Situation Calculus has been used by Scher1 and Levesque to represent beliefs and belief change without modal operators thanks to a predicate plays the role of an accessibility relation. Their approach has been extended by Shapiro et al. to support belief revision. In this extension plausibility levels are assigned to each situation, and the believed propositions are the propositions that are true in all the most plausible accessible situations. Their solution is quite elegant from a theoretical point of view but the definition of the plausibility assignment, for a given application domain, raises practical problems. This paper presents a new proposal that does not make use of plausibilities. The idea is to include the knowledge producing actions into the Successor State axioms. In this framework each agent may have a different Successor State axiom for a given fluent. Then, each agent may have his subjective view of the evolution of the world. Also, agents may know or may not know that a given action has been performed. That is, the actions are not necessarily public.
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theories of intentions in the framework of situation calculus
2004Co-Authors: Pilar Pozos Parra, Abhaya C Nayak, Robert DemolombeAbstract:We propose an extension of action theories to intention theories in the framework of situation calculus. Moreover the method for implementing action theories is adapted to consider the new components. The intention theories take account of the BDI (Belief-Desire-Intention) architecture. In order to avoid the computational complexity of theorem proving in modal logic, we explore an alternative approach that introduces the notions of belief, goal and intention fluents together with their associated Successor State axioms. Hence, under certain conditions, reasoning about the BDI change is computationally similar to reasoning about ordinary fluent change. This approach can be implemented using declarative programming.
Fangzhen Lin - One of the best experts on this subject based on the ideXlab platform.
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compiling causal theories to Successor State axioms and strips like systems
2011Co-Authors: Fangzhen LinAbstract:We describe a system for specifying the effects of actions. Unlike those commonly used in AI planning, our system uses an action description language that allows one to specify the effects of actions using domain rules, which are State constraints that can entail new action effects from old ones. Declaratively, an action domain in our language corresponds to a nonmonotonic causal theory in the situation calculus. Procedurally, such an action domain is compiled into a set of logical theories, one for each action in the domain, from which fully instantiated Successor State-like axioms and STRIPS-like systems are then generated. We expect the system to be a useful tool for knowledge engineers writing action specifications for classical AI planning systems, GOLOG systems, and other systems where formal specifications of actions are needed.
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from causal theories to Successor State axioms and strips like systems
2000Co-Authors: Fangzhen LinAbstract:We describe a system for specifying the efiects of actions. Unlike those commonly used in AI planning, our system uses an action description language that allows one to specify the efiects of actions using domain rules, which are State constraints that can entail new action efiects from old ones. Declaratively, an action domain in our language corresponds to a nonmonotonic causal theory in the situation calculus. Procedurally, such an action domain is compiled into a set of propositional theories, one for each action in the domain, from which fully instantiated Successor State-like axioms and STRIPS-like systems are then generated. We expect the system to be a useful tool for knowledge engineers writing action speciflcations for classical AI planning systems, GOLOG systems, and other systems where formal speciflcations of actions are needed.
Pilar Pozos Parra - One of the best experts on this subject based on the ideXlab platform.
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belief revision in the situation calculus without plausibility levels
2006Co-Authors: Robert Demolombe, Pilar Pozos ParraAbstract:The Situation Calculus has been used by Scher1 and Levesque to represent beliefs and belief change without modal operators thanks to a predicate plays the role of an accessibility relation. Their approach has been extended by Shapiro et al. to support belief revision. In this extension plausibility levels are assigned to each situation, and the believed propositions are the propositions that are true in all the most plausible accessible situations. Their solution is quite elegant from a theoretical point of view but the definition of the plausibility assignment, for a given application domain, raises practical problems. This paper presents a new proposal that does not make use of plausibilities. The idea is to include the knowledge producing actions into the Successor State axioms. In this framework each agent may have a different Successor State axiom for a given fluent. Then, each agent may have his subjective view of the evolution of the world. Also, agents may know or may not know that a given action has been performed. That is, the actions are not necessarily public.
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theories of intentions in the framework of situation calculus
2004Co-Authors: Pilar Pozos Parra, Abhaya C Nayak, Robert DemolombeAbstract:We propose an extension of action theories to intention theories in the framework of situation calculus. Moreover the method for implementing action theories is adapted to consider the new components. The intention theories take account of the BDI (Belief-Desire-Intention) architecture. In order to avoid the computational complexity of theorem proving in modal logic, we explore an alternative approach that introduces the notions of belief, goal and intention fluents together with their associated Successor State axioms. Hence, under certain conditions, reasoning about the BDI change is computationally similar to reasoning about ordinary fluent change. This approach can be implemented using declarative programming.
Sebastian Sardina - One of the best experts on this subject based on the ideXlab platform.
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incomplete causal laws in the situation calculus using free fluents
2016Co-Authors: Marcelo Arenas, Jorge A Baier, Juan S Navarro, Sebastian SardinaAbstract:We propose a simple relaxation of Reiter's basic action theories, based on fluents without Successor State axioms, that accommodates incompleteness beyond the initial database. We prove that fundamental results about basic action theories can be fully recovered and that the generalized framework allows for natural specifications of various forms of incomplete causal laws. We illustrate this by showing how the evolution of incomplete databases, guarded action theories, and non-deterministic actions can be conveniently specified.
