Constructing the Views Framework

Abstract. The views framework of Dinsdale-Young and others unifies several compositional techniques for reasoning about concurrent programs. This paper uses simple mathematics to construct the views framework incrementally from first principles. The result is a model for the views framework, which can also be understood as an independent theory of concurrent programs. Along the lines of “sequential programs are binary relations”, the theory adopts the maxim “con-current programs are formal languages”. Consequently, programs obey familiar algebraic laws that can simplify reasoning; there is no need to postulate opera-tional rules; the views program logic can be constructed in a stepwise fashion from more basic logics; program logic and operational thinking become largely decoupled; proving partial correctness becomes straightforward and it holds irre-spectively of the specific choice of programming language constructs, operational rules, and the atomic actions that are implemented in a computer. All theorems have been formally checked with Isabelle/HOL. A proof script is available online. Key words: semantics, formal languages, concurrency, programming calculi