Specification and Proof of Liveness Properties under Fairness Assumptions in B Event Systems

We present a proposal of specification and proof of liveness properties in B event systems under fairness assumptions. We give proof obligations in order to prove basic progress properties in B event systems under two types of assumptions: minimal progress and weak fairness. We define proof obligations in terms of weakest preconditions, which allow us to prove basic liveness properties as usual B proof obligations.We suggest the use of unity "Leads To" operator to specify more general liveness properties. In this way, we integrate the unity logic in the specification and proof of B event systems.