Peter Gammie

MCK: Model Checking the Logic of Knowledge

The specification formalism employed in model checking is usually some flavour of temporal or process algebraic language that expresses properties of the behavioural aspects of a system. Knowledge [5] is a modality that is orthogonal to the behavioural dimension, capturing properties of information flow. Logics of knowledge have been shown to be a useful framework for the analysis of distributed algorithms and security protocols, and model checking of these logics was first mooted by Halpern and Vardi [6]. Since that time theoretical aspects of model checking the logic of knowledge and its combinations with temporal logic have been studied [8–10]. The system MCK introduced in this paper implements parts of this theory.

Synchronous digital circuits as functional programs

Functional programming techniques have been used to describe synchronous digital circuits since the early 1980s. Here we survey the systems and formal underpinnings that constitute this tradition. We situate these techniques with respect to other formal methods for hardware design and discuss the work yet to be done.

Short note: Strict unwraps make worker/wrapper fusion totally correct

The worker/wrapper transformation is a general way of changing the type of a recursive definition, usually applied with an eye to increasing algorithmic efficiency. This note identifies an infelicity in the program transformations presented by Gill & Hutton (The worker/wrapper transformation, J. Funct. Program ., vol. 19, 2009, pp. 227–251) and proposes a new totally correct worker/wrapper fusion rule.