Hierarchical Correctness Proofs for Distributed Algorithms Hierarchical Correctness Proofs for Distributed Algorithms

This thesis introduces a new model for distributed computation in asynchronous net works the input output automaton This simple powerful model captures in a novel way the game theoretic interaction between a system and its environment and allows funda mental properties of distributed computation such as fair computation to be naturally expressed Furthermore this model can be used to construct modular hierarchical cor rectness proofs of distributed algorithms This thesis de nes the input output automaton model and presents an interesting example of how this model can be used to construct such proofs Thesis supervisor Nancy A Lynch Title Ellen Swallow Richards Professor of Computer Science and Engineering