Presuppositions in Context: Constructing Bridges

About the book: The First International and Interdisciplinary Conference on Modelling and Using Context, Rio de Janeiro, January 1997, gave rise to the present book, which contains a selection of the papers presented there, thoroughly refereed and revised. The treatment of contexts as bona fide objects of logical formalisation has gained wide acceptance, following the seminal impetus given by McCarthy in his Turing Award address. The field of natural language offers a particularly rich variety of examples and challenges to researchers concerned with the formal modelling of context, and several chapters in the volume deal with contextualisation in the setting of natural language. Others adopt a purely formal-logical viewpoint, seeking to develop general models of even wider applicability. The 12 chapters are organised in three groups: formalisation of contextual information in natural language understanding and generation, the application of context in mechanised reasoning domains, and novel non-classical logics for contextual application

Programming language elements for correctness proofs

Formal methods are not used widely in industrial software development, because the overhead of formally proving program properties is generally not acceptable. In this paper we present an ongoing research project to make the construction of such proofs easier by embedding the proof system into a compiler. Using the introduced new programming language, the programmer writes formal specification first. The specification is to be refined using stepwise refinement which results in a proof. The compiler checks this proof and generates the corresponding program in a traditional programming language. The resulting code automatically fulfills the requirements of the specification. In this paper we present language elements to build specification statements and proofs. We give a short overview on the metaprogramming techniques of the language that support the programmer's work. Using a formal model we give the semantics of specification statements and refinements. We also prove the soundness of the basic algorithms of the compiler