Review of "Proofs and refutations: the logic of mathematical discovery" by Imre Lakatos. Cambridge University Press 1976.

We study a conservative extension of classical propositional logic distinguishing between four modes of statement: a proposition may be affirmed or denied, and it may be strong or classical. Proofs of strong propositions must be constructive in some ...

Probably the most significant result concerning cut-free sequent calculus proofs in linear logic is the completeness of focused proofs. This completeness theorem has a number of proof theoretic applications -- e.g. in game semantics, Ludics, and proof ...