The transformation language ELaX (Evolution Language for XML-Schema [16]) is a domain-specific language for modi-fying existing XML Schemas. ELaX was developed to ex-press complex modifications by using add, delete and up-date statements. Additionally, it is used to consistently log all change operations specified by a user. In this pa-per we present the rule-based optimization algorithm ROfEL (Rule-based Optimizer for ELaX) for reducing the number of logged operations by identifying and removing unneces-sary, redundant and also invalid modifications. This is an essential prerequisite for the co-evolution of XML Schemas and corresponding XML documents. 1
