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 ...

MIT Press recently published Fundamental Proof Methods in Computer Science, a book by Konstantine Arkoudas and David Musser, a professor emeritus of computer science at the Rensselaer Polytechnic ...

We give a direct proof of admissibility of cut and contraction for the contraction-free sequent calculus G4ip for intuitionistic propositional logic and for a corresponding multi-succedent calculus: ...