There are several approaches to formalizing knowledge. The concept of knowledge is often introduced by a special operator whose properties are defined by a number of axioms. A situation is then modelled by using this operator in problem-specific axioms. This article presents a different approach a first-order logical model which does not use any new operators. The properties of knowledge should...

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...

This paper proposes a deadlock prevention algorithm for Distributed Object Oriented Systems (DOOS) based on the popular resource ordering technique. In distributed object oriented system, objects are the resources requested by the transactions. Though resource-ordering technique is not new, novelty of the proposed deadlock prevention algorithm lies in exploiting the relationships among objects ...

We show the decidability of model checking PA-processes against several first-order logics based upon the reachability predicate. The main tool for this result is the recognizability by tree automata of the reachability relation. The tree automata approach and the transition logics we use allow a smooth and general treatment of parameterized model checking for PA. This approach is extended to h...

Given a first-order sentence, a model-checking computation tests whether the sentence holds true in a given finite structure. Data provenance extracts from this computation an abstraction of the manner in which its result depends on the data items that describe the model. Previous work on provenance was, to a large extent, restricted to the negation-free fragment of first-order logic and showed...

In this paper, we propose a translation from normal first-order logic programs under the answer set semantics to first-order theories on finite structures. Specifically, we introduce ordered completions which are modifications of Clark’s completions with some extra predicates added to keep track of the derivation order, and show that on finite structures, classical models of the ordered-complet...

In model-checking the systems under investigation often arise in the form of products. The compositional method, developed by Feferman and Vaught in 1959, fits to this situation and can be used to deduce the truth of a formula in the product from information in the factors. Building on earlier work of Wöhrle and Thomas (2004), we study first-order logic with reachability predicates over finitel...

where our definition of Rt+1 helps clarify the relationship of this equation to the usual consumption Euler equation (and you should think about why this is the right definition of the interest factor in this model). Now we show that this FOC is satisfied by a rule that says Ct = γYt, where γ = 1 − αβ. To see this, note first that the proposed consumption rule implies that Kt+1 = (1− γ)Yt. The ...

Some notions in mathematics can be considered relative. Relative is a term used to denote when the variation in the position of an observer implies variation in properties or measures on the observed object. We know, from Skolem theorem, that there are first-order models where R is countable and some where it is not. This fact depends on the position of the observer and on the instrument/langua...

We consider the model-checking problem for data multipushdown automata (DMPA). DMPA generate data words, i.e, strings enriched with values from an infinite domain. The latter can be used to represent an unbounded number of process identifiers so that DMPA are suitable to model concurrent programs with dynamic process creation. To specify properties of data words, we use monadic second-order (MS...