Sequents vs Hypersequents for Åqvist Systems

Enhancing cut-free expressiveness through minimal structural additions to sequent calculus is a natural step. We focus on Åqvist’s system \(\textbf{F}\) with cautious monotonicity (CM), a deontic logic extension of \(\textbf{S5}\) , for which we define a sequent calculus employing (semi) analytic cuts.The transition to hypersequents is key to develop modular and cut-free calculi for \(\mathbf{F + (CM)}\) and \(\textbf{G}\) , also supporting countermodel construction.