Actions of amenable groups and crossed products of Z-absorbing   C*-algebras
  We study actions of countable discrete amenable groups on unital separable simple nuclear Z-absorbing C*-algebras. Under a certain assumption on tracial states, which is automatically satisfied in the case of a unique tracial state, the crossed product is shown to absorb the Jiang-Su algebra Z tensorially. 
Yasuhiko Sato
math.OA