Abstract. We present here a case study developing a parallel program. The approach that we use combines refinement and decomposition techniques. This involves in the first step to abstractly specify the aim of the program, then subsequently introduce shared information between sub-processes via refinement. Afterwards, decomposition is applied to split the resulting model into sub-models for different processes. These sub-models are later independently developed using refinement. Our approach aids the understanding of parallel programs and reduces the complexity in their proofs of correctness.
Keywords: Event-B, parallel programs, decomposition, refinement.