On the Decidability of a Fragment of preferential LTL

14 Linear Temporal Logic (LTL) has found extensive applications in Computer Science and Artificial Intelligence, 15 notably as a formal framework for representing and verifying computer systems that vary over time. Non16 monotonic reasoning, on the other hand, allows us to formalize and reason with exceptions and the dynamics of 17 information. The goal of this paper is therefore to enrich temporal formalisms with non-monotonic reasoning 18 features. We do so by investigating a preferential semantics for defeasible LTL along the lines of that extensively 19 studied by Kraus et al. in the propositional case and recently extended to modal and description logics. The main 20 contribution of the paper is a decidability result for a meaningful fragment of preferential LTL that can serve as 21 the basis for further exploration of defeasibility in temporal formalisms. 22 2012 ACM Subject Classification Theory of computation → Modal and temporal logics 23