On the expressiveness of modal transition systems with variability constraints

We demonstrate that modal transition systems with variability constraints are equally expressive as featured transition systems, by defining a transformation of the latter into the former, a transformation of the former into the latter, and proving the soundness and completeness of both transformations. Modal transition systems and featured transition systems are widely recognised as fundamental behavioural models for software product lines and our results thus contribute to the expressiveness hierarchy of such basic models studied in other papers published in this journal.