Investigating Girard's new propositionnal calculus which aims at a large scale study of computation, we stumble quickly on that question: What is a multiplicative connective? We give here a detailed answer together with our motivations and expectations.

The main concern of this paper is the design of a noetherian and confluent normalization for LK 2. The method we present is powerful: since it allows us to recover as fragments formalisms as seemingly different as Girard's LC and Parigot's λμ, FD, delineates other viable systems as well, and gives means to extend the Krivine/Leivant paradigm of `programming-with-proofs' to classical logic ; it is painless: since we reduce strong normalization and confluence to the same properties for linear logic using (...) appropriate embeddings ; it is unifying: it organizes known solutions in a simple pattern that makes apparent the how and why of their making. A comparison of our method to that of embedding LK into LJ brings to the fore the latter's defects for these `deconstructive purposes'. (shrink)

We define an optimal proof-by-proof embedding of intuitionistic sequent calculus into linear logic and analyse the (purely logical) linearity information thus obtained.