Abstract. A business process often shows different variations in a large organisation, due to different legal requirements in different countries, deviations in the IT infrastructure, or organisational differences. These variants are documented in separate independent process models. Management of these variants imposes various challenges. Invariant behaviour needs to be identified and redundancies among the variants have to be avoided. In this paper, we address these questions by defining a set-algebra for behavioural profiles. These profiles represent a behavioural abstraction of process models that can be computed efficiently. We trace back many questions of process variability management to set-theoretic operations and relations defined for behavioural profiles. As a validation, we apply our approach to an industry model collection.