Coalgebraic modal logic serves as a unifying framework to study a wide range of modal logics beyond the relational realm, including probabilistic and graded logics as well as conditional logics and logics based on neighbourhoods and games. Coalgebraic predicate logic (CPL), a generalization of a neighbourhoodbased first-order logic introduced by Chang, has been identified as a natural first-ord...

Proposition 3. If A=〈A,∧,∨, ·, \, /, 1, γ〉 is a residuated lattice with a nucleus γ, then the algebra Aγ=〈Aγ ,∧,∨γ , ·γ , \, /, γ(1)〉 is a residuated lattice, where Aγ=γ[A] and for all x, y ∈ Aγ , x ∨γ y=γ(x ∨ y) and x ·γ y=γ(x · y). For a variety V of residuated lattices with modal operators, consider V∗, the full subcategory of V consisting of those pairs 〈B, 〉 such that B generates B as a re...

Spatial constraint systems are algebraic structures from concurrent constraint programming to specify spatial and epistemic behavior in multi-agent systems. We shall use spatial constraint systems to give an abstract characterization of the notion of normality in modal logic and to derive right inverse/reverse operators for modal languages. In particular, we shall identify the weakest condition...

We consider a simple modal logic whose non-modal part has conjunction and disjunction as connectives and whose modalities come in adjoint pairs, but are not in general closure operators. Despite absence of negation and implication, and of axioms corresponding to the characteristic axioms of (e.g.) T, S4 and S5, such logics are useful, as shown in previous work by Baltag, Coecke and the first au...

Studying combined logics is a growing trend in applied logic. The general question is this: Suppose language L 3 has been formed by fusion of two languages L 1 and L 2. Let two logics L 1 and L 2 be defined over L 1 and L 2 , respectively. What can be said about conservative extensions L 3 in L 3 ? This is a fairly broad problem. Conservative extensions are not unique, and they may have differe...

In this paper we present a method for translating Horn clauses extended with modalities and embedded implication (which provide reasoning capabilities in a multiagent situation and hypothetical reasoning) into Horn clauses, therefore suitable for SLD resolution. The translation takes two steps: the rst one eliminates embedded implications by introducing new modalities; the second eliminates mod...

We explore the modal possibility operator and its dual necessity operator in qualitative data analysis , and show that it (quite literally) complements the derivation operator of formal concept analysis; we also propose a new generalisation of the rough set approximation operators. As an example for the applicability of the concepts we investigate the Morse data set which has been frequently st...

We extend propositional Gödel logic by a unary modal operator, which we interpret as 5 Gödel homomorphisms, i.e. functions [0, 1] → [0, 1] that distribute over the interpretations of the 6 binary connectives of Gödel logic. We show that validity in the propositional fragment has a simple 7 superintuitionistic Hilbert-type proof system, which is not structurally complete, and that validity 8 doe...