Soft Constraints in Feature Models

Feature Models represent admissible configurationsof products in Software Product Lines. Constraints areused to represent domain specific knowledge, such asrequiring or excluding a feature in the presence of another.Configurations failing to conform to these constraints aredeemed invalid. However, in many cases useful domaininformation cannot be expressed comfortably with suchforceful, hard constraints. Therefore, we propose the use ofsofter constraints of less forcing nature. We categorizepossible semantics for such constraints, analyze their impacton the feature expression and describe some specific analysisprocedures that are unique to the use of soft constraints.