Modal definability in Euclidean modal logics

TL;DR

This paper investigates the computability of modal definability within Euclidean modal logics, identifying which logics lead to undecidable definability problems based on their frame classes.

Contribution

It characterizes Euclidean modal logics that result in undecidable modal definability problems, advancing understanding of their computational properties.

Findings

Identifies Euclidean modal logics with undecidable definability problems

Provides a characterization of frame classes related to undecidability

Enhances understanding of the computational limits of Euclidean modal logics

Abstract

This paper is about the computability of the modal definability problem in classes of frames determined by Euclidean modal logics. We characterize those Euclidean modal logics such that the classes of frames they determine give rise to an undecidable modal definability problem.