More, the authors in  have shown that every well-posed linear system in [L.sup.1] is weakly regular, if the adjoint of its associated [C.sub.0] -semigroup is also a [C.sub.0]-semigroup.
Well-posed linear systems in [L.sup.1] and [L.sup.[infinity]] regular.
While extending the theory of dynamic stabilization to regular linear systems (a subclass of the well-posed linear systems
), it was shown in [7, Example 2.3] that even the standard observer-based controller is not a well-posed linear system
and its transfer function is not well-posed.
The basic theory of well-posed linear systems
has previously been scattered among myriad papers, each one rehearsing the entire history and development of the theory up to the time of writing, reports Staffans (mathematics, Abo Akademi U., Finland), and he finds the situation pretty tedious.