2 problems

Let $\mathbf{QS5}$ be the quantified modal logic QS5, and consider its fragment using two individual variables and a single unary predicate letter. Decidability conjecture. The fra…

Let $\mathbf{QS5}$ be the quantified modal logic QS5, and consider its fragment using two individual variables and two unary predicate letters. Undecidability conjecture. The fragm…