Composition operators on the discrete analogue of generalized Hardy   space on homogenous trees
  In this paper, we study the basic properties such as boundedness and compactness of composition operators on discrete analogue of generalized Hardy space defined on a homogeneous rooted tree. Also, we compute the operator norm of composition operator when inducing symbol is automorphism of a homogenous tree. 
Perumal Muthukumar and Saminathan Ponnusamy
math.FA