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 ...

This is a preview. Log in through your library . Abstract A propositional system of modal logic is second-order if it contains quantifiers ∀p and ∃p, which, in the standard interpretation, are ...

This is a preview. Log in through your library . Abstract Jaśkowski's discussive logic D₂ was formulated with the help of the modal logic S5 as follows (see [7, 8]): A ∊ D₂ iff ┌ A ┐ ∊ S5, where (-) ...

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 ...