[Formalism in software engineering?]

The basic issues are first illustrated by a case study, namely Jackson's method. The state-of-the-art in formalisation techniques for software engineering is then discussed, in particular the expression of successive states in developments and that of transitions between states. Two avenues of research are then presented: on the one hand, the use of logic, structured, and constructive techniques to express integrated fashion states, transitions, and their properties; on the other hand, the possible application of methods for representing incomplete of heuristic knowledge. As a conclusion, some general conjectures are stated.Francai