“…In data refinement 2 , some variables in the abstract machine are replaced by other variables in the refined machine; in this case, a gluing invariant is added in the refined machine to define the relation between the abstract variables and the newly introduced, concrete ones. Refinement in Event-B has been used to model numerous protocols and systems, including smart cash card systems 31 , vehicle platoons 32 , topology discovery in graphs 33 , self-recovery in sensor-actor networks 34 , spacecraft systems 35 , coordination in peer-to-peer networks 36 , smart grid recoverability 37 , proactive routing in wireless networks 38 , reaction networks 14 , etc.…”