Tradition states that above the entrance to Plato’s Academy were inscribed the words, “Let no one ignorant of geometry enter here.” A student in the modal logic interim course studies how subjunctives ...

A simple, bivalent semantics is defined for Łukasiewicz's 4-valued modal logic Łm4. It is shown that according to this semantics, the essential presupposition underlying Łm4 is the following: A is a ...

We investigate properties of prepositional modal logic over the class of finite structures. In particular, we show that certain known preservation theorems remain true over this class. We prove that a ...