Eternity Variables to Simulate Specifications

Simulation of specifications is introduced as a unification and generalization of refinement mappings, history variables, forward simulations, prophecy variables, and backward simulations. Eternity variables are introduced as a more powerful alternative for prophecy variables and backward simulations. This formalism is semantically complete: every simulation is a composition of a forward simulation, an extension with eternity variables, and a refinement mapping. This result does not need finite invisible nondeterminism and machine closure as in the Abadi-Lamport Theorem. Internal continuity is replaced by preservation of quiescence