Reasoning about programs via operational semantics: requirements for a support system.

Reasoning about programs using "axioms" is well established; in this paper we argue that reasoning about a program directly in terms of Structural Operational Semantic (SOS) language descriptions is a viable addition and that this is anyway necessary for the vast majority of languages where there is nothing like a full axiomatic description. Using an SOS description is likely to require detailed proofs whose acceptability to users will depend on suitable support systems. The paper presents a very simple example to illustrate how we can reason about (in fact, develop) a program to prove that it satisfies a specification. The main contribution is to use this trivial example to point out issues in designing an interactive proof system for constructing such proofs. [ABSTRACT FROM AUTHOR]