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This article extends and improves work on tableau-based decision methods for hybrid logic by Bolander and Braüner [5]. Their paper gives tableau-based decision procedures for basic hybrid logic (with unary modalities) and the basic logic extended with the global modality. All their proof procedures make use of loop-checks to ensure termination. Here we take(More)
This paper is about the good side of modal logic, the bad side of modal logic, and how hybrid logic takes the good and fixes the bad. In essence, modal logic is a simple formalism for working with relational structures (or multi-graphs). But modal logic has no mechanism for referring to or reasoning about the individual nodes in such structures, and this(More)
In their simplest form, hybrid languages are propositional modal languages which can refer to states. They were introduced by Arthur Prior, the inventor of tense logic, and played an important role in his work: because they make reference to specific times possible, they remove the most serious obstacle to developing modal approaches to temporal(More)
Hybrid languages have both modal and rst-order characteristics: a Kripke semantics, and explicit variable binding apparatus. This paper motivates the development of hybrid languages, sketches their history, and examines the expressive power of three hybrid binders. We show that all three binders give rise to languages strictly weaker than the corresponding(More)
A modal logic is developed to deal with nite ordered binary trees as they are used in (computational) linguistics. A modal language is introduced with operators for thèmother of', ` rst daughter of' and`second daughter of' relations together with their transitive reeexive closures. The relevant class of tree models is deened and three linguistic(More)