“…Hoare & He [24] show how the alphabetised relational calculus can be applied to construct a hierarchy of such theories, including simple imperative programs (relations), designs that correspond to preand postcondition specifications, and various theories of concurrent and parallel programs, including the process algebras ACP, CCS, and CSP [23]. Since the advent of UTP, a host of additional UTP theories have been developed that variously tackle paradigms like real-time programming [34], object-oriented programming [32], security and confidentiality [3], mobile processes [33], probabilistic modelling [6], and hybrid systems [15]. Moreover, the FMI API itself has been given a UTP-based semantics [9] that can be used as an interface to the semantic model of individual FMUs, and also allows a network of FMUs to be verified at this level using the FDR3 refinement checker [18].…”