Correspondence, Canonicity, and Model Theory for Monotonic Modal Logics

TL;DR

This paper explores coalgebraic predicate logic's application to monotonic modal logics, establishing key theorems that extend classical results to neighborhood frames and their subclasses.

Contribution

It proves analogues of the Goldblatt-Thomason and Fine's Canonicity Theorems for classes of monotonic neighborhood frames within coalgebraic predicate logic.

Findings

Established Goldblatt-Thomason analogue for monotonic neighborhood frames.

Proved Fine's Canonicity Theorem analogue for these frames.

Extended classical theorems to various subclasses of neighborhood frames.

Abstract

We investigate the role of coalgebraic predicate logic, a logic for neighborhood frames first proposed by Chang, in the study of monotonic modal logics. We prove analogues of the Goldblatt-Thomason Theorem and Fine's Canonicity Theorem for classes of monotonic neighborhood frames closed under elementary equivalence in coalgebraic predicate logic. The elementary equivalence here can be relativized to the classes of monotonic, quasi-filter, augmented quasi-filter, filter, or augmented filter neighborhood frames, respectively. The original, Kripke-semantic versions of the theorems follow as a special case concerning the classes of augmented filter neighborhood frames.