Perturbations of Positive Semigroups on AM-Spaces
  We consider positive perturbations of positive semigroups on AM-spaces and prove a result which is the dual counterpart of a famous perturbation result of Desch in AL-spaces. As an application we consider unbounded perturbations of the shift semigroup. 
A. B\'atkai, B. Jacob, J. Voigt, J. Wintermayr
math.FA