De nability and Unde nability with Real Order at the Background

Negative De nability in Modal Logic

The aim of this paper is to give characterizations of the notion of negative de nability as introduced in Venema This notion can be seen as an alternative way of de ning classes of Kripke frames via a modal language one that enables us for instance to de ne the previously unde nable class of irre exive frames Besides a list of closure conditions for negatively de nable classes the paper contain...

Axioms for De nability and Full Completeness

Algebraic Characterizations of Two Beth Deenability Properties

In the present paper we will show that the Beth de nability property corresponds to surjectiveness of epimorphisms in abstract algebraic logic. Furthermore, we will give an equally general characterization of the weak Beth de nability property, hereby giving a solution to Problem 14 in [Sa 88]. Finally, we will present two counterexamples showing that two of the more striking assumptions impose...

On e Upon a Time in the WestDetermina y , de nability , and omplexity of path games ?

Recognizability Equals De nability for Partial k Paths

We prove that every recognizable family of partial k paths is de nable in a counting monadic second order logic We also show the obstruction set of the class of partial k paths computable for every k