Atlee, Joanne M.Beidu, SandyFahrenberg, UliLegay, Axel2019-12-232019-12-232015-09http://hdl.handle.net/10012/15375Featured Transition Systems (FTSs) is a popular representation for software product lines: an entire product line is compactly represented as a single transition-machine model, in which feature-specific behaviour is guarded by feature expressions that are satisfied (or not) by the presence or absence of individual features. In previous work, FTS models were monolithic in the sense that the modeller had to construct the full FTS model of the product line in its entirety. To allow for modularity of FTS models, we propose here a language for extending an existing FTS model with new features. We demonstrate the language using a running example and present results about the language’s expressivity, commutativity of feature extensions, feature interactions, and resolution of such interactions.enConference Paper