“…By definition of synchronous product, it follows that for each i ∈ I, (s 2 , s 3 ) −→ µ 2,i × µ 3 ∈ T 2,3 , hence we have the combined transition (s 2 , s 3 ) −→ c µ 2 × µ 3 . By standard properties of lifting (see, e.g., [23]), it follows that µ 1 ×µ 3 L(R ) µ 2 ×µ 3 , as required. It is worthy to note that the unfolding mapping might transform an IMDP to a PA with an exponentially larger size.…”