“…In (Wong and Wonham, 1996), the abstraction is obtained in the form of a reporter map, which projects strings of events of the original (low-level) model, built from a set Σ, into highlevel strings built from an independent set T of events. Due to some difficulties with the use of reporter maps (Feng and Wonham, 2010), most of the approaches subsequent to (Wong and Wonham, 1996) focus on abstractions ob-tained by the natural projection, which maps strings of the original model into strings of the abstraction, by erasing events of Σ which are not contained in a given subset of relevant events Σ r ⊆ Σ, like in (Wong et al, 2000;Cunha and Cury, 2007;Feng and Wonham, 2008;Schmidt and Breindl, 2008).…”