Special Issue on Multi-Level Modeling Process Challenge Editorial

Multi-level modeling is an extension of traditional two-level object-oriented modeling which over the years has spawned several related solution technologies. These technologies embody a variety of multi-level modeling approaches, with differences spanning the range between superficial detail to fundamental divergence. Understanding those differences, as well as the respective trade-offs of different technologies can be difficult when looking at each technology in isolation and/or when technology demonstration application scenarios are not standardized. This EMISAJ special issue invited solutions to a multi-level modeling process challenge (Almeida et al. 2021), in order to allow contributors to showcase advantages and discuss shortcomings of their technologies. The contributions featured in this special issue therefore do not only support a deeper understanding of each technology respectively, but in combination also support comparisons among technologies.