Extended feature algebra [Extended Abstract]

Feature algebra was introduced as an abstract framework for feature oriented software development. One goal is to provide a common,clearly defined basis for the key ideas of feature orientation. We first present concrete models for the original axioms of feature algebra which represent the main features of feature oriented programs. However, these models show that the axioms of the feature algebra do not reflect some aspects of feature orientation properly. Hence we modify the axioms and introduce the concept of an extended feature algebra. Since the extension is also a generalisation, the original algebra can be retrieved by a single additional axiom. Last but not least we introduce more operators to cover concepts like overriding in the abstract setting