We show how formal specifications can be integrated into one of the current pragmatic object-oriented software development methods. Jacobson’s “Object-Oriented Software Engineering ” (OOSE) process is combined with object-oriented algebraic specifications by extending object and interaction diagrams with formal annotations. The specifications are based on Meseguer’s rewriting logic and are written in a meta-level extension of the language Maude by process expressions. As a result any such diagram can be associated with a formal specification, proof obligations ensuring invariant properties can be automatically generated, and the refinement relations between documents at different abstraction levels can be formally stated and proved. 1

. The specification language TROLL light is designed for the conceptual modeling of information systems. Maude is a logic programming language, which unifies the two paradigms of functional and concurrent object-oriented programming. Because of the very similar features offered by both languages, we present a translation from TROLL light concepts into the Maude language in order to compare the languages. Apart from presenting the translation, the languages are briefly described and illustrated by examples. 1 Introduction Various approaches for the specification of complex software systems have appeared recently, for example: Specification of functions (VDM, Z [Jon86, BHL90]), abstract data types [EM85, EGL89, EM90, Wir90], predicate logic and extensions like temporal and modal logic [MP91], semantic data models [HK87], and process specification (CCS [Mil80], CSP [Hoa85], petri nets [Rei85]). Recent Trends in Data Type Specification (ADT'92) H. Ehrig, F. Orejas (Eds.), Springer, Berl...

. Within the compound project KorSo our team is concerned with the research on techniques and methods for the development of reliable information systems on the basis of formal specifications. Our work focuses on the specification language TROLL light which allows to describe the part of the world which is to be modeled as a community of concurrently existing and communicating objects by determining their structure as well as their behavior. Moreover we develop and implement a computer aided specification environment for TROLL light which permits a prototyping animation as well as the proof of properties of specifications. 1 Introduction Proc. 5th Int. Conf. Advanced Information Systems Engineering (CAiSE'93) C. Rolland, F. Bodart, C. Cauvet (Eds.), Springer, Berlin, LNCS 685, pp. 463-483 (1993) Several approaches for the specification of complex software systems have been put forward in recent years, for example: Specification of functions (VDM, Z [Jon86, BHL90]), abstract data type...