datum: 17.10.2018 v 16:00
název: Checking cohesiveness in canonical models
přednášející: Matteo Pascucci (TU Vienna)
místo konání: UI, 2.patro, místnost č.318

souhrn: In their presentation of canonical models for normal systems of modal logic, Hughes and Cresswell observe that some of these models are based on a frame which can be also thought of as a collection of isolated frames, since its domain includes at least one pair of states that are not related by any accessibility walk; they call such frames ?non-cohesive?. The problem of checking whether the canonical model of a given system is cohesive is still rather unexplored and no general decision procedure is available. In this presentation we show that canonical models of some relevant classes of normal monomodal and bimodal systems are always non-cohesive.