Proceedings Fourth Workshop on Proof eXchange for Theorem Proving

This volume of EPTCS contains the proceedings of the Fourth Workshop on Proof Exchange for Theorem Proving (PxTP 2015), held as part of the International Conference on Automated Deduction (CADE 2015) on August 2-3, 2015 in Berlin. The PxTP workshop series brings together researchers working on various aspects of communication, integration, and cooperation between reasoning systems and formalisms. These proceedings contain seven regular papers, as well as the abstracts of the invited talks by Georges Gonthier (Microsoft Research) and Bart Jacobs (University of Leuven).