peer-reviewedUncontrolled software architecture erosion can lead to a de- gradation of the quality of a software system. It is hence of great importance to repair erosion e ciently. Refactor- ings can help to systematically reverse software architecture erosion through applying them in the system where archi- tectural violations have been detected. However, existing refactoring approaches do not address architecture erosion holistically. In this paper, we describe and formalize the theoreti- cal problem of repairing eroded software systems by nd- ing optimal repair sequences. Furthermore, we investigate the applicability and limitations of existing refactoring ap- proaches. We argue, true to the motto \more knowledge means les...