Philippe Balbiani

Constructive S4 modal logics with the finite birelational frame property

2024 · arXiv (Cornell University)

The logics $\mathsf{CS4}$ and $\mathsf{IS4}$ are the two leading intuitionistic variants of the modal logic $\mathsf{S4}$. Whether the finite model property holds for each of these logics have been long-standing open problems. It was recently …