9803876 Change propagation is a key part of software maintenance and evolution. The change starts with the programmer changing a component of software. After the change, the component may no longer fit with the rest of the software, because it may no longer provide what the other components require, or it may now require different services from the other components. In order to reintroduce the consistency into software, the programmer must keep track of inconsistencies and the locations where the secondary changes are to be made. The secondary changes, however, may introduce new inconsistencies, etc. The process continues until all inconsistencies are removed. The formal model of change propagation is based on graph rewriting. It covers specific scenarios, including strict change-and-fix, random change-and- fix, and top-down. The research includes development of a prototype tool based on the formalism, which keeps track of the remaining inconsistencies in software, and marks the components to be updated. The validation of both the formal model and the tool will be done by a case study. The results of the case study will serve as a feedback, and will be projected into both the model and the prototype tool.***
