Bicomplex Linear Operators on Bicomplex Hilbert Spaces and Littlewood's   Subordination Theorem
  In this paper we study some basic properties of bicomplex linear operators on bicomplex Hilbert spaces. Further we discuss some applications of Hahn-Banach theorem on bicomplex Banach modules. We also introduce and discuss some bicomplex holomorphic function spaces and prove Littlewood's Subordination principle for bicomplex Hardy space. 
Romesh Kumar and Kulbir Singh
math.FA