Composition operators on Orlicz-Sobolev spaces
  The kernel of composition operator $C_T$ on Orlicz-Sobolev space is obtained. Using the kernel, a necessary and a sufficient condition for injectivity of composition operator $C_T$ has been established. Composition operators on Orlicz-Sobolev space with finite ascent as well as infinite ascent have been characterized. 
Ratan Kumar Giri, Debajyoti Choudhuri
math.FA math.AP