Relative Nondeterministic Information Logic is EXPTIME-complete

Issue title: New Frontiers in Scientific Discovery – Commemorating the Life and Work of Zdzislaw Pawlak

Article type: Research Article

Authors: Demri, Stéphane | Orłowska,

Affiliations: Laboratoire Spécification et Vérification, CNRS & INRIA Futurs & ENS de Cachan 61, av. Pdt. Wilson, 94235 Cachan Cedex, France. E-mail: demri@lsv.ens-cachan.fr | National Institute of Telecommunications, ul. Szachowa 1, 04-894 Warsaw, Poland. E-mail: orlowska@itl.waw.pl

Abstract: We define a relative version of the logic NIL introduced by Orłowska, Pawlak and Vakarelov and we show that its satisfiability is not only decidable but also EXPTIME-complete. Such a logic combines two ingredients that are seldom present simultaneously in information logics: frame conditions involving more than one information relation and relative frames. The EXPTIME upper bound is obtained by designing a well-suited decision procedure based on the nonemptiness problem of Büchi automata on infinite trees. The paper provides evidence that Büchi automata on infinite trees are crucial language acceptors even for relative information logics with multiple types of relations.

Keywords: information logic, relative frame, computational complexity, Büchi tree automaton

Journal: Fundamenta Informaticae, vol. 75, no. 1-4, pp. 163-178, 2007