The state-of-the-art definitions of actual cause by Pearl and Halpern suffer from the modest expressivity of causal models. We develop a new definition of actual cause in the context of situation calculus (SC) basic action theories. As a result, we avoid the paradoxes that arise in causal models and can identify complex actual causes of conditions expressed in first-order logic. We provide a fo...

A calculus of events is presented in which domain constraints, concurrent events, and events with non-deterministic effects can be represented. The paper offers a non-monotonic solution to the frame problem for this formalism that combines two of the techniques developed for the situation calculus, namely causal and state-based minimisation. A theorem is presented which guarantees that temporal...

We consider a modified version of the situation calculus built using a two-variable fragment of the first-order logic extended with counting quantifiers. We mention several additional groups of axioms that need to be introduced to capture taxonomic reasoning. We show that the regression operator in this framework can be defined similarly to regression in the Reiter’s version of the situation ca...

An agent will generally have incomplete and possibly inaccurate knowledge about its environment. In addition, such an agent may receive erroneous information, perhaps in being misinformed about the truth of some formula. In this paper we present a general approach to reasoning about action and belief change in such a setting. An agent may carry out actions, but in some cases may inadvertently e...

In this paper, we present an approach to representing a core part of the knowledge consists of semantic information of common verbs from semantic dictionaries. We provide a meta-language as the representation framework for the rewritten knowledge of common verbs and their corresponding user tasks. The meta-language is interpreted based on transition systems, which can be realized on various for...

We show that designing large situation calculus theories can be simplified by using object-oriented techniques and tools together with established solutions to the frame problem. Situation calculus (McCarthy & Hayes 1969) is one of the leading logical representations for action and change, but large situation calculus theories are not easy to design and maintain, nor are they flexible for exten...

> Gelfond and Lifschitz introduce a declarative language A for describing eeects of actions and describe translations of theories in this language into extended logic programs. In this paper we extend the language A and its translation to allow reasoning about the eeects of concurrent actions. The logic programming formalization of situation calculus with concurrent actions presented in the pap...

In the AAAI-97 paper by McCain and Turner, the frame problem is solved using a nonmonotonic causal logic. In this note we show how their method can be adapted to the language of the situation calculus. The \causal situation calculus" is applied to action domains involving ramiications and nondeterminism, and related to the causal formalization of actions proposed by Lin.

In the situation calculus, it is sometimes necessary to prove that certain properties are true in all world states accessible from the initial state. This is the case for some forms of reasoning about the physical world, for certain planning applications, and for verifying integrity constraints in databases. Not surprisingly, this requires a suitable form of mathematical induction. This paper m...

Actions depend crucially on what an agent knows and does not know. For example, an action may have a precondition that requires knowing the referent of a term, which is generally referred to as knowing who or knowing what. Alternatively, executing a sense action may be the result of realizing that the referent of a term is not known yet. The latter requires an agent to reason about all it knows...