In a seminal paper Lin and Reiter introduced the notion of progression for basic action theories in the situation calculus. The idea is to replace an initial database by a new set of sentences which reflect the changes due to an action. Unfortunately, progression requires secondorder logic in general. In this paper, we introduce the notion of strong progression, a slight variant of Lin and Reit...

One important defect of Reiter’s default logic is inability to reason by cases. To overcome the defect definition of Reiter’s extension. Roos presents a modified definition of a default extension that solves the problem. In this paper, we will discuss the properties of Roos-extension that similar to Reiter-extension, and will find some properties of Reiter-extension cannot still correct to Roos...

The situation calculus, as proposed by McCarthy and Hayes, and developed over the last decade by Reiter and co-workers, is reconsidered. A new logical variant is proposed that captures much of the expressive power of the original, but where certain technical results are much more easily proven. This is illustrated using two existing non-trivial results: the regression theorem and the determinac...

Pinto and Reiter have argued that the Sit uation Calculus improved with time han dling axioms subsumes the features of lin ear time temporal formalisms such as Event Calculus and Interval Logic In this note we nd answers to some of their re marks by showing a modi ed version of Event Calculus that seems to match Sit uation Calculus handling of hypothetical reasoning and projection Further consi...

Background Reactive arthritis, Reiter’s syndrome is one of the seronegative arthropathies, that can be associated with intestinal infections (Shigella, Salmonella, Yersinia, Campylobacter jejuni, Clostridium difficile), sexual infections (Chlamydia trachomatis, Ureaplasma urealyticum) and lung infections (Chlamydia pneumoniae, Mycoplasma pneumoniae). Reiter’s syndrome is an arthritis that occur...