arXiv:2611.07919v1 Announce Type: new Abstract: We present a novel approach for model checking fault-tolerant distributed algorithms: instead of building large, monolithic algorithm models, we propose a modular approach where the user decomposes the algorithm into modules, verifies them individually, and replaces them with a synchronous abstraction. To enable our technique, we introduce a new system model that combines aspects of threshold automata and global synchronization protocols. We investigate the expressiveness of our new model, and present a (bounded) model checking procedure as well as a method for checking the correctness of the abstraction step. We implemented the technique and report on promising experimental results on a case study