brucker.ea:hol-ocl:2008 BookSection Heidelberg Springer-Verlag 2008 Fundamental Approaches to Software Engineering (FASE08) 4961 97-100 BruckerAchimD WolffBurkhart FiadeiroJosé InverardiPaola HOL-OCL – A Formal Proof Environment for UML/OCL We present the theorem proving environment HOL-OCL that is integrated in a MDE framework. HOL-OCL allows to reason over UMLclass models annotated with OCL specifications. Thus, HOL-OCL strengthens a crucial part of the UML to an object-oriented formal method. HOL-OCL provides several derived proof calculi that allow for formal derivations establishing the validity of UML/OCL formulae. These formulae arise naturally when checking the consistency of class models, when formally refining abstract models to more concrete ones or when discharging side-conditions from model-transformations.