This volume contains the proceedings of the Fourth Biennial Conference on F- mal Methods in Computer-Aided Design (FMCAD). The conference is devoted to the use of mathematical methods for the analysis of digital hardware c- cuits and systems. The workreported in this bookdescribes the use of formal mathematics and associated tools to design and verify digital hardware systems. Functional veri?cation has become one of the principal costs in a modern computer design e?ort. FMCAD provides a venue for academic and industrial researchers and practitioners to share their ideas and experiences of...