We present a new model of classical linear logic based on the notion of strong stability that was introduced recently in a work about sequentiality written jointly with Antonio Bucciarelli.

We examine the problem of finding fully abstract translations between programming languages, i.e., translations that preserve code equivalence and nonequivalence. We present three examples of fully abstract translations: one from call-by-value to lazy PCF, one from call-by-name to call-by-value PCF, and one from lazy to call-by-value PCF. The translations yield lower bounds on decision procedures for proving equivalences of code. We define a notion of ‘functional translation’ that captures the essence of the proofs of full abstraction, and show that some languages cannot be translated into others.

This paper tackles the problem of constructing a compact, point-free proof of the associativity of demonic composition of binary relations and its distributivity through demonic choice. In order to achieve this goal, a definition of demonic composition is proposed in which angelic composition is restricted by means of a so-called ‘monotype factor’. Monotype factors are characterised by a Galois connection similar to the Galois connection between composition and factorisation of binary relations. The identification of such a connection is argued to be highly conducive to the desired compactness of calculation.

Two imperative programming language phrases interfere when one writes to a storage variable that the other reads from or writes to. Reynolds has described an elegant linguistic approach to controlling interference in which a refinement of typed λ-calculus is used to limit sharing of storage variables; in particular, different identifiers are required never to interfere. This paper examines semantic foundations of the approach.

We describe a category that has (an abstraction of) interference information built into all objects and maps. This information is used to define a ‘tensor’ product whose components are required never to interfere. Environments are defined using the tensor, and procedure types are obtained via a suitable adjunction. The category is a model of intuitionistic linear logic. Reynolds' concept of passive type - i.e. types for phrases that do not write to any storage variables - is shown to be closely related, in this model, to Girard's ‘of course’ modality.