Resumen
Practioners and researchers of Object Management Group Inc. (OMG) has adopted Unified Modeling Language (UML) ever since OMG's foundation in 1997. It is highlighted that UML needs to be executable and translatable so that developers' models are interchangeable across the entire tool chain. UML models that are freely interchangeable, executable, and translatable represent the foundation of the Object Management Group's Model Driven Architecture (MDA), making possible a world in which software expressed as UML models, not only as code, is an asset. A layered UML with a small well-defined, executable, and translatable nucleus enables and supports development of a tool chain so that developers can build, verify and compile models to multiple targets as technology changes and employ other yet-to-be-invented tools to ensure model correctness and completeness. None of this is possible unless UML is layered and its specification built from a small set of components automatically merged together to ensure correctness. Only then can UML models be truly executable, translatable, and interchangeable assets, fully realizing the vision of MDA.