Simulating without Negation
Natasha Kurtonina, Maarten de Rijke · Journal of Logic and Computation · 1997
Although negation-free languages are widely used in logic and computer science, relatively little is known about their expressive power.To address this issue we consider kinds of non-symmetric bisimulations called directed simulations, and use these to analyse the expressive power and model theory of negation-free modal and temporal languages.We first use them to obtain preservation, safety and definability results for a simple negation-fret modal language.We then obtain analogous results for stronger negation-free languages.Finally, we extend our methods to deal with languages with non-Boolean negation.