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 ...

Modal logic, an extension of classical logic, investigates the modes of truth such as necessity and possibility. Its development has been closely intertwined with advances in proof theory, a field ...

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 ...