Natural Deduction: A Proof-Theoretical Study - Dag Prawitz - Google Books

http://books.google.de/books?id=IosnAAAACAAJ

An innovative approach to the semantics of logic, proof-theoretic semantics seeks the meaning of propositions and logical connectives within a system of inference. Gerhard Gentzen invented proof-theoretic semantics in the early 1930s, and Dag Prawitz, the…